docs(f6): any-file behavior + Ctrl+Alt+D wording (#19)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

README.md

@@ -132,26 +132,32 @@ record per the contract; git push/pull is the transport, no re-homing ever.
 
 Design: `vscode-cowriting-plugin-content/specs/coauthoring-cross-rung-format.md`.
 
-## F6 — Diff-view toggle (Feature #17)
+## F6 — Diff-view toggle (Feature #17, #19)
 
-**Cmd/Ctrl-Alt-D** (or **Cowriting: Toggle Diff View**) flips a tracked
-document into a native `vscode.diff` against a **coauthoring baseline** — the
-readonly baseline on the left, your **live, editable** document on the right
-(so you keep writing inside the diff; toggling again closes it). The diff
-answers "what did *I* change?" in one keystroke instead of git archaeology.
+**`Ctrl+Alt+D`** (the same chord on macOS — not `Cmd`; or **Cowriting: Toggle
+Diff View**) flips the focused document into a native `vscode.diff` against a
+**coauthoring baseline** — the readonly baseline on the left, your **live,
+editable** document on the right (so you keep writing inside the diff; toggling
+again closes it). The diff answers "what did *I* change?" in one keystroke
+instead of git archaeology.
 
+- **Works on any file (#19):** any document you can edit — a file inside or
+  outside the workspace folder, or an **untitled** scratch buffer. Only a
+  non-text-editor focus warns. (Untitled buffers diff in-memory; saving makes
+  the baseline persist.)
 - **Machine-factored baseline (INV-18):** the baseline initializes when a doc
-  is first tracked and **advances automatically at every machine landing**
-  (every successful `applyAgentEdit` seam apply — INV-9). So text Claude landed
-  never shows as a change; everything the diff shows is operator-authored by
+  is first seen and **advances automatically at every machine landing** (every
+  successful `applyAgentEdit` seam apply — INV-9). So text Claude landed never
+  shows as a change; everything the diff shows is operator-authored by
   construction — no attribution filtering.
 - **Pin on demand:** **Cowriting: Pin Diff Baseline to Now** resets the
   baseline to the current buffer for a deliberate "review my next pass" epoch;
   the diff tab title names the epoch (`opened` / `Claude landed` / `pinned`).
 - **Pure view, repo-free (INV-19):** the baseline snapshot lives in VS Code
-  workspace storage, **never** the repo — `.threads/`, the cross-rung contract
-  (INV-14..17), and `SCHEMA_VERSION` are untouched. Storage-unavailable
-  degrades to in-memory baselines + one warning.
+  **global** extension storage, keyed by a hash of the document URI, **never**
+  the repo — `.threads/`, the cross-rung contract (INV-14..17), and
+  `SCHEMA_VERSION` are untouched. Storage-unavailable degrades to in-memory
+  baselines + one warning.
 - **No LLM in CI:** host E2E (`test/e2e/suite/diffView.test.ts`) drives the same
   programmatic seam ingress (propose + accept) the F4 suite uses.
 

docs/MANUAL-SMOKE-F6.md

@@ -6,10 +6,11 @@ rest of F6 needs no credentials and no network.
 
 1. `npm run build`, launch the extension (F5 in VS Code opens the committed
    `sandbox/` playground), open `playground.md`.
-2. Edit a sentence by hand, then **Cmd/Ctrl-Alt-D** (or run **Cowriting: Toggle
-   Diff View**). ✅ A diff opens: the readonly baseline on the left, your live
-   document on the right; the tab title reads `playground.md — my changes since
-   opened <time>`. Your hand edit shows as a change.
+2. Edit a sentence by hand, then **`Ctrl+Alt+D`** (same chord on macOS — not
+   `Cmd`; or run **Cowriting: Toggle Diff View**). ✅ A diff opens: the readonly
+   baseline on the left, your live document on the right; the tab title reads
+   `playground.md — my changes since opened <time>`. Your hand edit shows as a
+   change.
 3. Keep typing **in the diff's right pane**. ✅ Editing continues in place;
    decorations/threads still work. Toggle again. ✅ The diff tab closes and the
    normal editor is back.
@@ -21,6 +22,9 @@ rest of F6 needs no credentials and no network.
    now); the title reads `pinned <time>`. Type → your changes show against the
    pin.
 6. Reload the window (Developer: Reload Window). ✅ Toggle: the baseline is the
-   same as before the reload (persisted in workspace storage, not the repo —
-   INV-19; `git status` shows nothing new).
-7. Toggle on a file outside the workspace folder. ✅ A warning, no diff.
+   same as before the reload (persisted in **global** extension storage, not the
+   repo — INV-19; `git status` shows nothing new).
+7. **Any file (#19):** open a file from *outside* the `sandbox/` folder, or a
+   new untitled buffer (`Cmd/Ctrl+N`), edit it, and `Ctrl+Alt+D`. ✅ The diff
+   opens there too — untitled buffers show `(unsaved)` in the title and diff
+   in-memory. Toggle with focus on a non-editor (e.g. the terminal) → warning.