fix(plugins): make the 10 focused plugins installable, finish the AgentHub rename

The ten `agenthub-*` plugins were listed by the marketplace but could never be
installed — two schema mistakes present since the entries were first authored
(57dc915), both invisible until you actually run `claude plugin install`:

- marketplace entries used `"path": "plugins/<name>"`; the CLI only accepts
  `"source"`, so every one failed with
  `This plugin's marketplace entry is invalid: source: Invalid input`
- each `plugin.json` carried npm's `"repository": { "type", "url" }` object;
  the schema wants a plain string, so the next attempt failed with
  `Validation errors: repository: Invalid input`

Verified by installing all 11 entries into a throwaway CLAUDE_CONFIG_DIR:
1/11 before, 11/11 after. `plugins-marketplace.test.js` was asserting the
broken shape, which is why CI stayed green — it now asserts `source` and
rejects `path`.

Marketplace renamed `claude-code-agent-monitor-plugins` -> `agenthub`, so the
install line is `agenthub@agenthub`. ARCHITECTURE.md documented a marketplace
name (`smartgift-claude-code-monitor`) that never existed in any revision.

The documented `/plugin marketplace add Smartgift-AI/Claude-Code-Monitor` also
never worked: the `owner/repo` shorthand resolves to github.com only, and this
repo is self-hosted on Gitea. Confirmed the CLI rejects `host/owner/repo` and
ignores GH_HOST / GITHUB_HOST / CLAUDE_CODE_MARKETPLACE_URL, so the full
https:// clone URL is the only supported form. Same GitHub-habit class fixed
elsewhere: raw.githubusercontent.com icon URLs (404, and the repo ships
favicon.svg not favicon.ico — the client had the same dead /favicon.ico),
a smartgift.github.io docs link (404), and Gitea `/blob/<ref>/` paths that
must be `/src/branch/<ref>/`.

Repository renamed to Smartgift-AI/AgentHub throughout. Gitea 301-redirects
the old name, so these were stale rather than broken; `docs/superpowers/`
keeps the old name because those are dated decision records.

Adds `repo-links.test.js` to guard both classes (it runs under the existing
pre-commit gate) plus an openapi.yaml drift check — the committed spec had
silently fallen a minor version behind package.json. `generate-openapi-yaml.js`
now exports `render()` so the test compares against one definition of the dump
options instead of a second copy.

client/src/hooks/useNotifications.ts

@@ -123,9 +123,9 @@ async function notify(title: string, body: string) {
     try {
       if ("serviceWorker" in navigator) {
         const registration = await navigator.serviceWorker.ready;
-        await registration.showNotification(title, { body, icon: "/favicon.ico", silent: false });
+        await registration.showNotification(title, { body, icon: "/favicon.svg", silent: false });
       } else {
-        new Notification(title, { body, icon: "/favicon.ico" });
+        new Notification(title, { body, icon: "/favicon.svg" });
       }
     } catch {
       // Silently ignore

client/src/lib/__tests__/agentOriginLabel.test.ts

@@ -127,9 +127,7 @@ describe("agentOriginLabel - parent chain walk", () => {
 
 describe("projectFromCwd - session-cwd fallback for the dir prefix", () => {
   it("returns the last path segment of a POSIX cwd", () => {
-    expect(projectFromCwd("/Users/dev/WebstormProjects/Claude-Code-Agent-Monitor")).toBe(
-      "Claude-Code-Agent-Monitor"
-    );
+    expect(projectFromCwd("/Users/dev/WebstormProjects/AgentHub")).toBe("AgentHub");
   });
 
   it("ignores a trailing slash", () => {

client/src/lib/types.ts

@@ -1235,7 +1235,7 @@ export interface UpdateStatusPayload {
    *  Drives whether the "Update available" call-to-action is shown. */
   update_available: boolean;
   /** Absolute path to the detected git repository root. Example:
-   *  `"/Users/dev/Claude-Code-Agent-Monitor"`. */
+   *  `"/Users/dev/AgentHub"`. */
   repo_root?: string;
   /** Resolved ref compared against, e.g. "upstream/master" or "origin/main";
    *  null when no remote could be resolved (e.g. no remotes configured). */