feat(settings): one page per section with a grouped nav and search

Settings moves from a tab bar to /settings/<section>: a left nav grouped
General / Agents / Routing / Git / Projects (a select on narrow screens), a
search box over every section (Ctrl/Cmd+F, Enter opens the first match), and
row primitives. Each AI tool has its page under agents/<id>, the AI Tools
modal becomes the Agents page, Pricing shows every vendor, Git → Worktrees
sets which untracked worktrees the sidebar lists, and each project gets a
page with its own worktree override and Forget all. ?tool= and #ai-tools
links redirect to the path form.

client/src/lib/projectTreePrefs.ts

@@ -3,7 +3,8 @@
  * ONE localStorage key (`agenthub.sidebar.projects`): which projects are
  * collapsed, whether a repo's untracked worktrees are listed, and which
  * worktree sources (`claude` = `<repo>/.claude/worktrees/*`, `agenthub` =
- * LANES_ROOT) are hidden. A `useSyncExternalStore` reader that caches nothing
+ * LANES_ROOT) are hidden — globally, or per project root, where a project's own
+ * list (Settings → Projects) replaces the global one. A `useSyncExternalStore` reader that caches nothing
  * but the parsed blob for the current raw string, so the sidebar and Settings
  * can never disagree. Nothing here reaches the server.
  * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
@@ -17,9 +18,16 @@ export interface ProjectTreePrefs {
   collapsed: Record<string, boolean>;
   showUntracked: boolean;
   hideSources: string[];
+  /** Per project root: replaces `hideSources` for that project. */
+  projectHideSources: Record<string, string[]>;
 }
 
-const DEFAULTS: ProjectTreePrefs = { collapsed: {}, showUntracked: true, hideSources: [] };
+const DEFAULTS: ProjectTreePrefs = {
+  collapsed: {},
+  showUntracked: true,
+  hideSources: [],
+  projectHideSources: {},
+};
 const listeners = new Set<() => void>();
 let cache: { raw: string | null; value: ProjectTreePrefs } = { raw: null, value: DEFAULTS };
 
@@ -41,6 +49,10 @@ export function readProjectTreePrefs(): ProjectTreePrefs {
       collapsed: parsed.collapsed && typeof parsed.collapsed === "object" ? parsed.collapsed : {},
       showUntracked: parsed.showUntracked !== false,
       hideSources: Array.isArray(parsed.hideSources) ? parsed.hideSources : [],
+      projectHideSources:
+        parsed.projectHideSources && typeof parsed.projectHideSources === "object"
+          ? parsed.projectHideSources
+          : {},
     };
   } catch {
     value = DEFAULTS;
@@ -58,6 +70,11 @@ export function writeProjectTreePrefs(patch: Partial<ProjectTreePrefs>): void {
   listeners.forEach((l) => l());
 }
 
+/** The sources hidden for one project: its own override, else the global list. */
+export function hiddenSourcesFor(prefs: ProjectTreePrefs, root: string | null): string[] {
+  return (root !== null && prefs.projectHideSources[root]) || prefs.hideSources;
+}
+
 function subscribe(l: () => void) {
   listeners.add(l);
   return () => listeners.delete(l);