Give the card window's title field its Escape abandon

The field's exits were commit-only, silently diverging from the board
rename's Escape-abandons rule, and Escape was ambiguous with the body in
Edit mode. Settled: Escape reverts to the on-disk title and focuses the
body; the collision resolves by focus per 06's first-responder routing.

Claude-Session: https://claude.ai/code/session_01HJ7PhFNmQ19bvy9RMD6GSb

DESIGN/05-card-window.md

@@ -8,7 +8,7 @@ The standalone per-card window. Opened by fast double-click, ⌘↩, or the cont
 
 Two full-height columns: a wide **body column** (leading) and a narrow **attributes sidebar** (trailing), each scrolling independently. Visual reference: [assets/card-sidebar-reference.png](assets/card-sidebar-reference.png) — a GitLab-style issue pane; its *pattern* (stacked small-caps sections, quiet read-first rows, actions at the bottom) is what carries over, not its enhanced-schema content.
 
-- **Body column, top to bottom**: the **title field** — large, borderless; edits write through to frontmatter on commit (Return or focus loss); clearing it removes the `title` key (titles are optional — the untitled placeholder shows here as on the face); Return commits and moves focus into the body. Beneath it, a **quiet created/modified line** ("Created ⟨date⟩ · Modified ⟨date⟩ · by ⟨modified-by⟩", secondary styling, omitting whichever keys are absent — the "by" segment renders only when the self-reported provenance stamp is present, 01-storage-format.md; this is provenance made visible where git history may not exist) — the read-only readout the pathfinder dropped with its inspector, back where the mockup puts it. Then the **body** (Preview/Edit, below).
+- **Body column, top to bottom**: the **title field** — large, borderless; edits write through to frontmatter on commit (Return or focus loss); clearing it removes the `title` key (titles are optional — the untitled placeholder shows here as on the face); Return commits and moves focus into the body. **Escape abandons** (settled — the board inline rename's abandon, applied here): the field reverts to the on-disk title and focus moves into the body, never a commit. The Edit-mode collision resolves by focus, 06-history-undo.md's first-responder rule: while the title field is focused, Escape is the title abandon even with the body in Edit; with the body editor focused, Escape is the Edit→Preview flip as specified. Beneath it, a **quiet created/modified line** ("Created ⟨date⟩ · Modified ⟨date⟩ · by ⟨modified-by⟩", secondary styling, omitting whichever keys are absent — the "by" segment renders only when the self-reported provenance stamp is present, 01-storage-format.md; this is provenance made visible where git history may not exist) — the read-only readout the pathfinder dropped with its inspector, back where the mockup puts it. Then the **body** (Preview/Edit, below).
 - **Attributes sidebar**: everything about the card that isn't the body — sections below. Fixed narrow width derived from font metrics (full relative scaling, 10-accessibility.md); the window's resize flex goes to the body.
 
 (The pathfinder's compositions are both gone: the metadata bar — labels, assignees, due — left with those fields' move to the enhanced schema, and the horizontal attachments strip dissolves into the sidebar.)

DESIGN/11-command-nexus.md

@@ -67,6 +67,7 @@ All board grammar keys are inert while a title editor is focused, and menu dispa
 | Return | Card window, Preview | Enter Edit |
 | Escape | Card window, Edit | Return to Preview |
 | Return | Card window, title field | Commit title, focus into body |
+| Escape | Card window, title field | Abandon: revert to the on-disk title, focus into body — routes by focus, winning over Edit-mode's Escape while the field is focused (05) |
 | Escape / ⌘↩ | Card window, source mode | Cancel / Apply (leaving-by-toggle is Apply too — 05) |
 | Arrows / Space / Return / ⌫ | Card window, attachments section focused | Row navigation / QuickLook / open / Remove to *system* Trash (05) |