feat: implement repository clone mode with SSH key support

- Add clone_mode and branch fields to tool_instances
- Add ssh_key_id to git_repositories for per-repo SSH key assignment
- Implement host-side git cloning with branch selection (default: main)
- Mount SSH keys into containers for git operations in clone mode
- Add dirty state check on clone-mode instance deletion with confirmation
- Update SessionsPage with mount/clone selector, branch input, SSH key display
- Add SSH key selector to repository creation form
- Add dirty delete confirmation modal with changed files list
- Update API schemas and endpoints for new fields
- Sync delta specs to main specs (git-repo, tool-instances, repo-clone-mode)
- Archive completed OpenSpec change: repo-clone-mode-with-ssh
- Document git requirement for custom tool types

Quality gates: Frontend typecheck and build passed
OpenSpec: repo-clone-mode-with-ssh archived with all tasks complete

apps/web/src/pages/settings.tsx

@@ -9,8 +9,6 @@ type SettingsStatus = "loading" | "ready" | "error";
 const TABS = [
   { label: "General", path: "general" },
   { label: "SSH Keys", path: "ssh-keys" },
-  { label: "Tool Types", path: "tool-types" },
-  { label: "Tool Configs", path: "tool-configs" },
 ] as const;
 
 const THEME_OPTIONS = [
@@ -106,7 +104,7 @@ export const SettingsPage = () => {
           <p className="eyebrow">Configuration</p>
           <h1>Settings</h1>
         </div>
-        <p className="muted">General preferences, SSH keys, tool types, and tool configs live here.</p>
+        <p className="muted">General preferences and SSH keys.</p>
       </header>
 
       <nav className="settings-tabs" aria-label="Settings sections">