fix(fs): persist read window offset in the read card meta

An empty read window (byte cap below the first selected line: `lines: []`
with `totalLines > 0`) dropped `offset` from the persisted presentation
meta, so a replayed read card could not report where the window starts or
where a continuation resumes. Carry `offset` on `FsReadMeta`,
`ReadResultView`, and the `presentationMeta` projection, and validate it in
`readMetaFromMeta` (1-based integer; the first line number may not fall
below it). Re-record the ACP fixtures and the cordis api catalog.

Also correct the Note's `parallel-file-reads` golden path
(examples/tui-agent -> apps/cli) and record the pre-card replay-degradation
tradeoff in the Decision section.

packages/core/tools/src/presentation.ts

@@ -207,6 +207,12 @@ export interface ReadResultView {
   title?: string
   /** The read file's path (the model-facing path; the bridge relativizes it). */
   path: string
+  /**
+   * The 1-based first line the window requested, preserved even when `lines` is
+   * empty (a byte cap below the first selected line yields an empty window) so a
+   * UI knows where the window starts and where a continuation resumes.
+   */
+  offset: number
   /** The returned window's lines, in file order, each keeping its file line number. */
   lines: ReadFileLine[]
   /** Exact total line count in the file, so a UI can show a "showing N of M" affordance. */