fix(ui): keep a focus the row menu moved when closing the Session Manager (#509 review)

- _restoreOverlayFocus(key, modal) now leaves focus alone when something
  outside the overlay already holds it (not <body>, not inside the modal).
  The Session Manager's "Switch to session" and "Open folder" call
  selectSession() before closeSessionManager(), and the restore was pulling
  focus back from the terminal to the header button. Both close methods pass
  their modal; a regression test drives that order.
- Test harness: focusHarness() routes getElementById through a local binding
  instead of leaking globalThis.__els, and its modal stubs report their own
  search box as contained, as the real DOM does.
- CLAUDE.md and docs/architecture-invariants.md: record that the global
  Escape handler calls every close method on every Escape (capture phase),
  so a close method with side effects must return early when not open.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

CLAUDE.md

@@ -335,7 +335,7 @@ Frontend JS modules have `@fileoverview` with `@dependency`/`@loadorder` tags. L
 
 **Welcome "Resume Conversation" list** (terminal-ui.js): `loadHistorySessions()` fetches once and caches the corpus on `_historyAll`/`_historyCases`; every subsequent view (filter box, sort select, expand, the periodic refresh in panels-ui.js) goes through `_renderHistoryList()`, so never append rows to `#historyList` directly or re-fetch to re-sort. ⚠️ The box height is **class-driven**: expanding the list without `.history-list.expanded` leaves the collapsed `max-height` in place and just deepens a scroll well, which is the bug #260 reported (35 sessions in a ~4-row box). ⚠️ The A–Z sort keys off `_historyRowLabel()`, the SAME string the row renders (`name || firstPrompt || path`), most rows are transcript-backed and have no session name, so sorting on `name` alone silently does nothing. ⚠️ A filter implies expansion, and `_renderSearch()` hides `#historyHeader` (title + controls) as one unit while a search is active. Tests: `test/history-list-controls.test.ts`.
 
-**Command palette + shortcut registry**: `Ctrl/Cmd/Alt+K` opens the session palette; shortcuts live in a rebindable registry (`DEFAULT_SHORTCUTS`/`getShortcutRegistry()`/`matchesShortcutEvent()` in app.js, overrides in `settings.shortcutOverrides`). ⚠️ Palette-chord keys must ALSO be swallowed in `attachCustomKeyEventHandler` (terminal-ui.js) or xterm writes the control byte into the PTY. ⚠️ `saveAppSettings()` rebuilds settings from the DOM, so keys edited elsewhere (`shortcutOverrides`, `showTokenCount`, `showCost`) need explicit `_prev` carry-over. ⚠️ **Smart copy (`Ctrl+C`)**: with no selection it must `return true` without `preventDefault()` or the interrupt is lost; keep `copyTerminalSelection` out of `SHORTCUT_ACTIONS`. The gate tests the CLEANED selection (`CodemanCopySelection.clean`: trailing padding, plus a LEADING margin only up to the width the CLI declares in `capabilities.transcriptGutter`, never one derived from the pane); the strip is not idempotent, so clean once and pass the RAW selection on, and leave Alt+drag column selections untouched. → [architecture-invariants#command-palette-and-shortcut-registry](docs/architecture-invariants.md#command-palette-and-shortcut-registry)
+**Command palette + shortcut registry**: `Ctrl/Cmd/Alt+K` opens the session palette; shortcuts live in a rebindable registry (`DEFAULT_SHORTCUTS`/`getShortcutRegistry()`/`matchesShortcutEvent()` in app.js, overrides in `settings.shortcutOverrides`). ⚠️ Palette-chord keys must ALSO be swallowed in `attachCustomKeyEventHandler` (terminal-ui.js) or xterm writes the control byte into the PTY. ⚠️ The global Escape handler (app.js) calls EVERY close method on every Escape, in the capture phase, so a close method that does more than hide (the palette and Session Manager restore focus) must return early when its overlay is not open. ⚠️ `saveAppSettings()` rebuilds settings from the DOM, so keys edited elsewhere (`shortcutOverrides`, `showTokenCount`, `showCost`) need explicit `_prev` carry-over. ⚠️ **Smart copy (`Ctrl+C`)**: with no selection it must `return true` without `preventDefault()` or the interrupt is lost; keep `copyTerminalSelection` out of `SHORTCUT_ACTIONS`. The gate tests the CLEANED selection (`CodemanCopySelection.clean`: trailing padding, plus a LEADING margin only up to the width the CLI declares in `capabilities.transcriptGutter`, never one derived from the pane); the strip is not idempotent, so clean once and pass the RAW selection on, and leave Alt+drag column selections untouched. → [architecture-invariants#command-palette-and-shortcut-registry](docs/architecture-invariants.md#command-palette-and-shortcut-registry)
 
 **Per-device vs synced settings**: the `displayKeys` set in settings-ui.js is a **client-side merge policy**, not a wire filter. A display key seeds from the server only when localStorage has no value for it, which is what prevents one device overwriting another; `showPlanUsageLimits` is additionally `delete`d from the incoming payload outright. Separately, `SettingsUpdateSchema` is `.strict()` and simply **does not declare** `skin`, `showFileViewerButton`, `showCronButton`, `webglRendererEnabled`, `localEchoEnabled`, `cjkInputEnabled`, or `extendedKeyboardBar`, so sending one of those is a validation error. The rest (`showResponseViewer`, `showPlanUsageLimits`, `language`, and most `show*` keys) ARE in the schema and do persist server-side; they are per-device by client policy only. ⚠️ Adding a new per-device setting means deciding **both** questions: membership in `displayKeys`, and presence in the schema.