Slice 6: right-click command menu + git write actions

git boundary: Pull/Push/Commit/DiscardAll (discard is 1.4-destructive). Scanner.RefreshRepo re-scans one repo after a mutation. Service GitFetch/GitPull/GitPush/GitCommit/GitDiscard record a git-* activity event and refresh on success; service.New takes a refresh hook. HTTP POST /api/repo/git. New <repo-menu> overlay with plain-language commands (Get latest/Publish/Check for updates/Save my work/Set active/Ask Claude to switch/Copy path/Discard all changes), summoned by repo-list's repo:contextmenu. Added service test for commit/discard on a temp repo. Verified the menu live for safe commands.

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

components/repo-list/repo-list.js

@@ -105,6 +105,15 @@ class RepoList extends HTMLElement {
     for (const r of this.#repos) {
       const li = document.createElement('li');
       if (r.path === this.#selected) li.classList.add('selected');
+      // Right-click opens the command menu (§6) for this repo — via an event,
+      // so <repo-menu> stays decoupled from this component (§1.1).
+      li.addEventListener('contextmenu', (e) => {
+        e.preventDefault();
+        this.dispatchEvent(new CustomEvent('repo:contextmenu', {
+          detail: { repo: r, x: e.clientX, y: e.clientY },
+          bubbles: true, composed: true,
+        }));
+      });
       li.innerHTML = `
         <span class="name">${this.#esc(r.name)}</span>
         <span class="branch">${this.#esc(r.branch || '—')}</span>