#46 (SLICE-3, accept): Accept all pending proposals in one gesture

Document-edit flow SLICE-3 — completes reach→review→accept
(specs/coauthoring-document-edit-flow.md §7.2, INV-42). A single "Accept all"
gesture applies every pending proposal on the current document through the
existing F4 acceptById seam (block proposals take the INV-40 word-precise path
automatically), in descending anchor order so an earlier accept never invalidates
a later one, skipping (never force-applying) proposals that can't anchor and
reporting applied-vs-skipped. Batched application of the existing accept path — no
new mechanism; the webview posts intent only (INV-35). No confirmation dialog
(undo restores).

- proposalController.ts: acceptAllProposals(document) → {applied, skipped}
  (descending order, orphan-skip); accept/acceptById gain a silent opt so the
  batch suppresses N per-proposal orphan warnings in favour of one report.
- trackChangesPreview.ts: ToolbarMsg += {type:"acceptAll"}; handleWebviewMessage
  routes it to a public acceptAll(document) that batches + reports.
- extension.ts + package.json: cowriting.acceptAllProposals command (active doc,
  markdown-gated palette entry) for the non-webview path.
- media/preview.ts + shellHtml: "✓✓ Accept all" toolbar button, posting the
  intent, shown only with ≥2 pending proposals (authorable, on-state).
- trackChangesModel.ts: diffToBlockHunks now emits one block-aligned hunk per
  CHANGED block even when changed blocks are ADJACENT (treats changed blocks as
  1:1 anchors alongside unchanged ones; gap-spans only cover add/remove runs
  between anchors) — fixes adjacent changed blocks collapsing into one proposal.
- f12Accept host E2E (apply-all reconstructs; orphan skip + report; single
  proposal; command registered/gated); MANUAL-SMOKE-F12 §3.

214 unit + 73/5 host E2E green. Completes the document-edit-flow cluster
(#42 reach + #47 review + #46 accept).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/extension.ts

@@ -107,6 +107,20 @@ export function activate(context: vscode.ExtensionContext): CowritingApi | undef
   );
   context.subscriptions.push(trackChangesPreviewController);
 
+  // #46 (INV-42): accept every pending proposal on the active doc in one gesture
+  // (also reachable from the preview toolbar's "Accept all" button). Reuses the
+  // batched F4 seam + reports applied-vs-skipped.
+  context.subscriptions.push(
+    vscode.commands.registerCommand("cowriting.acceptAllProposals", async () => {
+      const doc = vscode.window.activeTextEditor?.document;
+      if (!doc || doc.languageId !== "markdown") {
+        void vscode.window.showWarningMessage("Cowriting: open a Markdown document to accept its proposals.");
+        return;
+      }
+      await trackChangesPreviewController.acceptAll(doc);
+    }),
+  );
+
   // --- F6 machine-landing wiring — now for ANY authorable doc ---
   // The seam's single machine-landing signal advances the F6 baseline (INV-18);
   // the seam can now fire on out-of-folder files too, so wire it unconditionally.