fix(web): model erase-in-line, tab stops, and cross-line SGR

Six findings. Each terminal-semantics case was checked in a real terminal
(tmux, reading back the painted screen) before changing anything:

`100%\r\x1b[KOK` shows `OK`. Modelling the `\r` without its erase left the
previous frame's tail standing — a regression against the old truncate, since
`\r\x1b[K` is the single idiom every spinner and progress bar writes. Erase is
now part of the same replay, in all three parameter forms.

`a\tb\rXY` shows `XY      b`. Counting a tab as one column produced `XYb` and
destroyed the alignment this card exists to hold, so the cursor now advances
by terminal columns: tabs reach the next 8-column stop and a wide character
takes two cells.

`\x1b[31mabc\rX\nnext` paints BOTH lines red. A newline does not reset the
graphic state, so state threads from one replayed line to the next instead of
closing at each line end.

Only `m` accumulates into a cell's style now. Folding cursor and erase
sequences in grew the state string per redraw and emitted boundaries anser
had to discard.

The empty check reads the parsed lines the card renders rather than the raw
text: output that is only escapes or control bytes survives `trim()` yet
parses to nothing, and drew blank rows plus a copy control for invisible
bytes instead of the placeholder.

The gutter is the card's own left padding rather than a margin. Every render
site rewrites `margin` wholesale for its own indent, which silently cancelled
the reservation and let a container clip the dot.

The fixture sample no longer carries an `[exit code: 1]` line: the real bash
presenter consumes that marker precisely because the card shows the exit as
its own pill, so the built-bundle snapshot had pinned a frame showing it
twice — one the product path cannot produce.

.agents/notes/implemented/feature/2026-07-28-web-terminal-card.md

@@ -17,11 +17,11 @@ The Web client ignored it. `packages/client/ui-conversation/src/client/contract/
 The component's contract:
 
 - **Prompt lines, one per command line.** Each line of the command gets its own row: label, then that line verbatim. A `command` carrying two shell commands on two lines therefore reads as the two commands it is, instead of collapsing into one ellipsized row. The label is the cwd's last path segment, or `~` when the cwd equals the `home` prop — a browser has no `$HOME`, so the caller supplies the absolute home directory and the collapse simply does not apply without it. A view with no cwd renders a plain `$`. A trailing newline is a terminator, not an empty final command. Only the FIRST row carries the label: the view knows one working directory — where the call started — and a later line may run somewhere else entirely, since a `cd` in the command is enough to move it. Repeating the label down the rows would state a directory per line that nothing here knows, which is the same reason the run-state dot appears once. Later rows keep a bare `$` so they still read as prompts.
-- **One run-state dot for the call, on the first row.** `StateDot` in three of its four states: the chase while running, red for the exit status that also renders the pill, green for a clean settle — the same indicator a tool row's leading icon uses, so a row and its own card cannot disagree about one command. The dot exists because the first question a reader has about a shell command is whether it is still running, and without it that had to be inferred from the absence of output — which a settled command producing no output also looks like. It sits out of flow in a gutter reserved to the left of the card surface, so it neither indents its command nor depends on the command's own text metrics to line up with it. Exactly one dot, whatever the line count: the exit status the view carries is the whole call's, and bash reports no per-command status, so a dot per line would assert of a line that succeeded inside a failing call that the line itself failed. The single visually hidden text label carries the same scope, since `StateDot` is `aria-hidden` and one label per row would read to assistive technology as several distinct outcomes.
+- **One run-state dot for the call, on the first row.** `StateDot` in three of its four states: the chase while running, red for the exit status that also renders the pill, green for a clean settle — the same indicator a tool row's leading icon uses, so a row and its own card cannot disagree about one command. The dot exists because the first question a reader has about a shell command is whether it is still running, and without it that had to be inferred from the absence of output — which a settled command producing no output also looks like. It sits out of flow in a gutter the card reserves as its OWN left padding, so it neither indents its command nor depends on the command's text metrics to line up. The reservation is padding rather than margin because every render site rewrites `margin` wholesale to set its own indent, which silently cancelled a margin-based gutter and let a container clip the dot. Exactly one dot, whatever the line count: the exit status the view carries is the whole call's, and bash reports no per-command status, so a dot per line would assert of a line that succeeded inside a failing call that the line itself failed. The single visually hidden text label carries the same scope, since `StateDot` is `aria-hidden` and one label per row would read to assistive technology as several distinct outcomes.
 - **No soft wrapping.** Output lines are `white-space: pre` inside a horizontally scrolling box. Column alignment survives; a long line scrolls instead of folding.
 - **Height cap with an expand control.** Output longer than `DEFAULT_TERMINAL_MAX_LINES` (16) lines shows `ceil(max/2)` head lines plus the remaining tail lines, with a button in between that reports the hidden count and expands. The count is of parsed lines after the trailing output terminator is dropped, so an N-line output ending in a newline is N lines. The split arithmetic is the same as the TUI transcript's collapsed tool card (`packages/ui/tui/src/components/transcript.ts`), so one command's head and tail slices agree between the two front ends.
-- **ANSI color.** `anser` splits the SGR runs; `ui-primitives/src/ansi.ts` resolves each run into an inline style rendered as React spans. A foreground-only run maps the basic 16 colors onto `--dsw-*` theme tokens so authored color stays legible under both themes; a run that paints its own background keeps anser's literal rgb for both so its intended contrast survives, as do 256-palette, truecolor, and the two basic colors this design system has no token for. Sequences that carry no color (OSC strings, non-CSI escapes, inert C0 controls) are stripped before parsing so they never reach the DOM as literal characters. Cursor movements resolve before that strip, into a per-line column buffer rather than by string surgery, because carriage return and backspace only MOVE the cursor — neither erases anything, so what a reader sees is whatever each column last had written to it. `100%` then a carriage return and `OK` shows `OK0%`, since the redraw is shorter than the frame beneath it; a trailing `abc` plus a backspace still shows `abc`, since nothing overwrote the `c`; `abc` plus two backspaces and `XY` shows `aXY`. Each of these was checked against a real terminal, because the earlier truncate-and-delete approximations looked right and were not. SGR state is stamped per column as a terminal stores it per cell, so a partial overwrite keeps each surviving character's own color: red `bad`, three backspaces, then `ok` shows `okd` with the `d` still red. A CSI sequence occupies no column and changes only the state later writes are stamped with, which is also why a carriage return does not reset color.
-- **Exit status and copy.** A non-zero exit code or a signal renders a status pill, matching the exit-status distinction the bash tool's own renderer draws; a clean exit renders none, and settled empty output renders a dimmed placeholder. The copy control copies the raw output text, not the rendered tree, so the prompt line and the pill stay out of the clipboard.
+- **ANSI color.** `anser` splits the SGR runs; `ui-primitives/src/ansi.ts` resolves each run into an inline style rendered as React spans. A foreground-only run maps the basic 16 colors onto `--dsw-*` theme tokens so authored color stays legible under both themes; a run that paints its own background keeps anser's literal rgb for both so its intended contrast survives, as do 256-palette, truecolor, and the two basic colors this design system has no token for. Sequences that carry no color (OSC strings, non-CSI escapes, inert C0 controls) are stripped before parsing so they never reach the DOM as literal characters. Cursor movements resolve before that strip, into a per-line column buffer rather than by string surgery, because carriage return and backspace only MOVE the cursor — neither erases anything, so what a reader sees is whatever each column last had written to it. `100%` then a carriage return and `OK` shows `OK0%`, since the redraw is shorter than the frame beneath it; a trailing `abc` plus a backspace still shows `abc`, since nothing overwrote the `c`; `abc` plus two backspaces and `XY` shows `aXY`. Each of these was checked against a real terminal, because the earlier truncate-and-delete approximations looked right and were not. SGR state is stamped per column as a terminal stores it per cell, so a partial overwrite keeps each surviving character's own color: red `bad`, three backspaces, then `ok` shows `okd` with the `d` still red. A CSI sequence occupies no column and changes only the state later writes are stamped with, which is also why a carriage return does not reset color, and why SGR state threads from one line to the next rather than closing at each newline. Erase-in-line is part of the same replay, because `\r\x1b[K` is the single idiom every spinner and progress bar writes — modelling the `\r` alone left the previous frame's tail standing, which is text the terminal never showed. Only `m` accumulates into a cell's style; a cursor or erase sequence must not, or the state string grows per redraw and emits boundaries anser has to discard. The cursor advances by terminal columns, so a tab reaches the next 8-column stop and a wide character takes two: `a\tb` then a redraw of `XY` shows `XY      b`, since a two-character redraw cannot reach column 8.
+- **Exit status and copy.** A non-zero exit code or a signal renders a status pill, matching the exit-status distinction the bash tool's own renderer draws; a clean exit renders none, and settled empty output renders a dimmed placeholder — judged on the parsed lines the card renders, not on the raw text, since output that is only escapes or control bytes survives a `trim()` yet parses to nothing visible and would otherwise draw blank rows plus a copy control for invisible bytes. The copy control copies the raw output text, not the rendered tree, so the prompt line and the pill stay out of the clipboard.
 
 Geometry, radius, and fonts mirror `CodeBlock`, so a terminal card and a fenced code block match visually; `white-space: pre` plus horizontal scroll is the deliberate divergence. The clipboard write both components need moved out of `CodeBlock` into a package-internal `src/clipboard.ts`, unexported so it stays an implementation detail of the two blocks.
 
@@ -55,11 +55,11 @@ Inline rendering is licensed for the terminal intent alone. A future intent that
 
 ## Testing
 
-`packages/client/ui-primitives/tests/ansi.spec.ts` pins the parse layer: token mapping for the basic colors, literal rgb for the values with no token, the background-run pair, every decoration and the `textDecoration` collision between two of them, the sanitizing of OSC strings and non-CSI escapes and inert controls, per-line carriage-return redraws and backspace overwrites (including a backspace stopping at a line start and resolving after a redraw), and CRLF preservation. `packages/client/ui-primitives/tests/terminal-block.spec.tsx` pins the component: cwd shortening, the running/empty/settled arms, signal outranking exit code, the trailing-newline terminator rule, the head/tail cap with its `aria-expanded` toggle, the run-state dot across all three reachable states plus its position ahead of the prompt label, the one-row-per-command-line prompt and its single dot on the first row, and the copy control asserting raw output on both the accepted and refused clipboard paths, plus `writeClipboard` directly.
+`packages/client/ui-primitives/tests/ansi.spec.ts` pins the parse layer: token mapping for the basic colors, literal rgb for the values with no token, the background-run pair, every decoration and the `textDecoration` collision between two of them, the sanitizing of OSC strings and non-CSI escapes and inert controls, the cursor replay (redraws leaving a longer frame's tail standing, a trailing backspace erasing nothing, erase-in-line in all three parameter forms, tab stops, wide characters, SGR threading across lines, and a cursor/erase sequence never entering a cell style), and CRLF preservation. Each replay case was checked against a real terminal first. `packages/client/ui-primitives/tests/terminal-block.spec.tsx` pins the component: cwd shortening, the running/empty/settled arms, signal outranking exit code, the trailing-newline terminator rule, the head/tail cap with its `aria-expanded` toggle, the run-state dot across all three reachable states plus its position ahead of the prompt label, the one-row-per-command-line prompt and its single dot on the first row, and the copy control asserting raw output on both the accepted and refused clipboard paths, plus `writeClipboard` directly.
 
 `packages/client/ui-conversation/tests/terminal-card.spec.tsx` pins the wiring at every render site: `terminalCardModel`'s derivation and each of its null arms, the result title replacing the pending one, the cwd resolving against the session workspace across all four of its cases, the panel resetting the card's expand state when the selection changes, the chat row's expand-gated body against the panel's full-height one, `BashRow`'s resident card and its agreement with its own summary row's state dot, and the panel's Output section including the run_code sub-dispatch and the out-of-window head. That file is written against no gate pressure — `packages/client/ui-conversation/src/*` sits on the coverage `exclude` list in `vitest.config.ts`, so a coverage run over this package measures none of these files.
 
-`apps/web/tests/terminal-card.snapshot.ts` pins the assembled application over the built client bundles: the same render intent at both conversation render sites and in both chat-row shapes, because a bash call reaches a resident card only through the keyed `BashRow` registration and every other terminal-declaring tool name lands on the render-site fallback row, whose body is expand-gated. Fixture turn 65 was named `bash` and turn 60 left as `fx-bash` so one fixture covers both shapes, and turn 60's command was made two lines so the built-bundle snapshot pins the per-line prompt and its single dot (`dotsPerPromptRow: [1, 0]`). That terminal turn is ordered BEFORE the todo turn on purpose: the standing plan retires at the next `turn/start`, so appending it after would have emptied the dock's plan strip and taken the todo surfaces' own coverage with it; that turn also carries what turn 60's three clean lines cannot — SGR runs resolved to `--dsw-*` tokens, output past the chat cap, a nested cwd, and a non-zero exit recovered from the trailing marker.
+`apps/web/tests/terminal-card.snapshot.ts` pins the assembled application over the built client bundles: the same render intent at both conversation render sites and in both chat-row shapes, because a bash call reaches a resident card only through the keyed `BashRow` registration and every other terminal-declaring tool name lands on the render-site fallback row, whose body is expand-gated. Fixture turn 65 was named `bash` and turn 60 left as `fx-bash` so one fixture covers both shapes, and turn 60's command was made two lines so the built-bundle snapshot pins the per-line prompt and its single dot (`dotsPerPromptRow: [1, 0]`). That terminal turn is ordered BEFORE the todo turn on purpose: the standing plan retires at the next `turn/start`, so appending it after would have emptied the dock's plan strip and taken the todo surfaces' own coverage with it; that turn also carries what turn 60's three clean lines cannot — SGR runs resolved to `--dsw-*` tokens, output past the chat cap, a nested cwd, and a non-zero exit authored beside the sample. The sample's body deliberately carries NO `[exit code: N]` line: the real bash presenter consumes that marker out of the body precisely because the card shows the exit as its own pill, so leaving it in would pin a frame showing the exit twice — one the product path cannot produce.
 
 `apps/web/tests/navigation-panes.e2e.ts` adds the real-browser scenario over its existing `echo NAVIGATION_OK` bash call, asserting what jsdom cannot compute: squeezing the output pane below its content width leaves the line at one row and gives the pane horizontal overflow, the run-state dot resolves to the green success token rather than to a literal color (a `--dsw-*` var has no computed value at all without the real theme stylesheet) and starts to the left of the card surface itself, and the copy control reaches the page's own async Clipboard API rather than the `execCommand` fallback. Its `terminal-card.expected.md` golden records the resolved workspace in the prompt row, which is what a bash call with no `workdir` must show instead of a bare `$`.