Create command palette and add new features for search and actions (#728)

* refactor(ui): replace in-repo Command primitive with cmdk wrapper

* feat(command-palette): add global Cmd+K palette with v1 actions

* feat(command-palette): add session, file, and commit search sources

* refactor: add provider names to model constants

* feat(command-palette): add settings, navigation, message search, and ⌘K hints

* feat(command-palette): add git fetch/pull/push and branch switch actions

* refactor(command-palette): consolidate fetch source hooks behind useApiSource

* refactor(command-palette): extract useCommandKey and SETTINGS_MAIN_TABS metadata

* refactor(command-palette): extract groups into declarative registry

* refactor(command-palette): wire openFile through PaletteOpsContext

* refactor: migrate openSettings and refreshProjects from window.* to PaletteOpsContext

* refactor(command-palette): inline groups and delete registry indirection

* refactor(command-palette): return items array directly from source hooks

* refactor(palette-ops): flatten Handle wrapper into ref-based registry

* refactor: inline useCommandKey as MOD_KEY constant in two call sites

* feat: introduce pages and fix bug on branch switching

* fix: small labels

* fix: coderabbit issues

* fix: coderabbit comments

* Update src/components/chat/view/subcomponents/ProviderSelectionEmptyState.tsx

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

---------

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

src/components/command-palette/sources/useCommitsSource.ts

@@ -0,0 +1,35 @@
+import { authenticatedFetch } from '../../../utils/api';
+
+import { useApiSource } from './useApiSource';
+
+export type CommitResult = {
+  hash: string;
+  shortHash: string;
+  message: string;
+  author: string;
+};
+
+interface CommitsResponse {
+  commits?: Array<{ hash: string; message: string; author: string }>;
+  error?: string;
+}
+
+export function useCommitsSource(projectId: string | undefined, enabled: boolean) {
+  return useApiSource<CommitResult, CommitsResponse>({
+    enabled: enabled && !!projectId,
+    deps: [projectId],
+    fetcher: (signal) => {
+      const params = new URLSearchParams({ project: projectId!, limit: '50' });
+      return authenticatedFetch(`/api/git/commits?${params.toString()}`, { signal });
+    },
+    parse: (data) => {
+      if (!data.commits) return [];
+      return data.commits.map<CommitResult>((c) => ({
+        hash: c.hash,
+        shortHash: c.hash.slice(0, 7),
+        message: c.message,
+        author: c.author,
+      }));
+    },
+  });
+}