fix(client): address CI and review findings on blank-session reuse

- docs: fix cross-class note links (../feature/...), mirror the membership
  reuse criterion in README.zh.md and the connectWorkspace architecture
  note (EN/ZH/sidecars re-recorded)
- test(client): stray + member blank at the same path — the scan skips the
  stray and reuses the member
- test(web): re-registration after delete now mints a fresh blank session
  (the old cwd-only reuse is gone), so the account is no longer empty;
  assert the retained seeded session is still not re-adopted

.agents/notes/implemented/bug-fix/2026-08-05-workspace-blank-session-reuse-membership.md

@@ -8,7 +8,7 @@ English | [中文](2026-08-05-workspace-blank-session-reuse-membership.zh.md)
 
 Clicking the `+` on a Workspace group in the sidebar sometimes opened a session that the sidebar showed under Ungrouped instead of under the clicked Workspace — "entered a new session but the Workspace was not selected". The failure was specific to Workspaces registered at the directory the CLI runs from (in practice the harness checkout itself, i.e. `defaults.cwd = process.cwd()`), and appeared once a CLI-born blank session existed there.
 
-Root cause: `connectWorkspace`'s blank-session reuse scanned the session list mirror on `cwd` equality alone. The host's own membership rule requires **both** an id in the Workspace account (`sessionIds`) **and** a session header whose canonical cwd equals the Workspace path ([Workspace UI product flow](2026-07-25-workspace-ui-product-flow.md)); a cwd match without the account slot is exactly the Ungrouped case. The reuse scan ignored the account slot, so any **live blank** session whose cwd matched qualified — including `main-session-*` sessions the CLI/TUI/headless entry points birth at the host cwd (`session.create({})` falls back to `defaults.cwd` and never attaches to a Workspace). When such a session was live and blank (no `turn/start` yet), the next `+` click on a Workspace registered at that path reused it and navigation opened a session no grouping surface can show under that Workspace. Workspaces at other paths were unaffected because no unaccounted blank sessions accumulate there; the host-cwd Workspace accumulated one per CLI run.
+Root cause: `connectWorkspace`'s blank-session reuse scanned the session list mirror on `cwd` equality alone. The host's own membership rule requires **both** an id in the Workspace account (`sessionIds`) **and** a session header whose canonical cwd equals the Workspace path ([Workspace UI product flow](../feature/2026-07-25-workspace-ui-product-flow.md)); a cwd match without the account slot is exactly the Ungrouped case. The reuse scan ignored the account slot, so any **live blank** session whose cwd matched qualified — including `main-session-*` sessions the CLI/TUI/headless entry points birth at the host cwd (`session.create({})` falls back to `defaults.cwd` and never attaches to a Workspace). When such a session was live and blank (no `turn/start` yet), the next `+` click on a Workspace registered at that path reused it and navigation opened a session no grouping surface can show under that Workspace. Workspaces at other paths were unaffected because no unaccounted blank sessions accumulate there; the host-cwd Workspace accumulated one per CLI run.
 
 ## Decision
 
@@ -22,7 +22,7 @@ The reuse scan now requires workspace membership: `blank` AND `summary.cwd === w
 
 ## Consequences
 
-Stray blank sessions remain visible in Ungrouped (the user can still open them) but are never hijacked by a Workspace's New Session flow. A stale client mirror (Workspace frame lagging the account) can miss a reuse window and create instead — the pre-existing race behavior, already coalesced per Workspace. No host, wire, or durable-format change.
+Stray blank sessions remain visible in Ungrouped (the user can still open them) but are never hijacked by a Workspace's New Session flow. Membership is a new condition on the reuse scan, and it has one observable stale-mirror edge: in the window where the session mirror is fresh but the Workspace account frame lags, the Workspace's own member blank can fail the membership check and a duplicate blank is minted where the old code reused — a second `New Session` row under that Workspace rather than the old failure shape (a session that no grouping surface shows). Both windows are transient and the per-Workspace coalescing still prevents duplicate creates racing one another. No host, wire, or durable-format change.
 
 ## Testing