feat: per-tool settings, persistent settings file, Codex and Antigravity sessions, tokens and hooks (#40 B, C1, C2, D)

Part B: Model Pricing, Hook Configuration and CLAUDE_HOME move from
Settings → Dashboard to the Claude Code tab's AgentHub sub-tab
(ClaudeAgentHubSettings.tsx); CODEX_HOME is editable in Codex → AgentHub.
A home that is or contains the OS home is refused (EBADHOME).

Settings persistence: dashboard-saved settings go to
~/.config/agenthub/settings.env (AGENTHUB_SETTINGS_FILE), outside the plugin
cache an update wipes. Load order: real env > the checkout's .env > that file.
The first CLAUDE_HOME change pins DASHBOARD_DATA_DIR so the DB stays put.

C1: codex-usage.js reads Codex rollout journals into sessions (new column
tool) and token_usage, tracked per file in codex_rollouts; forks deduped by
total vector, sub-agent threads folded into the root; pricing-sync also
prices OpenAI models; PricingSettings with a vendor filter.

C2: codex-hooks.js installs AgentHub's hooks into $CODEX_HOME/hooks.json on
a click, through a stable forwarder; Codex trust is never written. The hook
route creates tool='codex' sessions and folds sub-agent hooks into the root.

D: antigravity-usage.js reads agy's per-conversation SQLite files (tokens
from ModelUsageStats) into tool='antigravity' sessions; antigravity-hooks.js
installs the named hook `agenthub` (PreInvocation, PostToolUse, Stop — never
PreToolUse) into ~/.gemini/config/hooks.json; Settings → Antigravity tab;
Gemini pricing.

Whole-change review fixes: sameOriginGuard on both home PUTs, routers.missing
on a CLAUDE_HOME change, reset-pricing scope, GET /api/sessions?tool=,
clear-data covering the new tables, Codex child-thread events moving no
status, hooks owning status only while current, EFOREIGN for a forwarder
that is not ours, agy quiet window and turn rules, AGENTHUB_SETTINGS_FILE
honoured from .env.

Docs, OpenAPI and the CLAUDE.md marker updated. Server 2141, client 779.

server/__tests__/hook-handler.test.js

@@ -5,7 +5,9 @@
  * local server to process the buffered request on its own schedule. These tests
  * lock in that non-blocking contract so a future refactor can't reintroduce the
  * "stuck running hooks" stall (handler waiting up to the per-request timeout for
- * a slow/busy/wedged dashboard to reply).
+ * a slow/busy/wedged dashboard to reply). Also: a Codex hook (second argument
+ * `codex`) is marked `tool: "codex"`, an Antigravity one `tool: "antigravity"`,
+ * and any other second argument is not passed on.
  * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
  */
 
@@ -46,10 +48,10 @@ function startMockServer({ responseDelayMs }) {
 
 // Spawn the real handler, pipe a hook payload to stdin, and time how long it
 // takes to exit.
-function runHandler({ port, hookType = "Stop", payload }) {
+function runHandler({ port, hookType = "Stop", payload, extra = [] }) {
   return new Promise((resolve, reject) => {
     const start = process.hrtime.bigint();
-    const child = spawn(process.execPath, [HANDLER, hookType], {
+    const child = spawn(process.execPath, [HANDLER, hookType, ...extra], {
       env: { ...process.env, CLAUDE_DASHBOARD_PORT: String(port) },
       stdio: ["pipe", "ignore", "ignore"],
     });
@@ -90,6 +92,34 @@ describe("hook-handler non-blocking delivery", () => {
     }
   });
 
+  it("marks a Codex hook with tool: codex, and a Claude hook with no tool at all", async () => {
+    const { server, port, received } = await startMockServer({ responseDelayMs: 0 });
+    try {
+      await runHandler({
+        port,
+        hookType: "PreToolUse",
+        payload: { session_id: "cx" },
+        extra: ["codex"],
+      });
+      await runHandler({ port, hookType: "PreToolUse", payload: { session_id: "cc" } });
+      await runHandler({
+        port,
+        hookType: "Stop",
+        payload: { session_id: "ag" },
+        extra: ["antigravity"],
+      });
+      await runHandler({ port, hookType: "Stop", payload: { session_id: "zz" }, extra: ["evil"] });
+      await new Promise((r) => setTimeout(r, 200));
+      const bodies = received.map((b) => JSON.parse(b));
+      assert.equal(bodies.find((b) => b.data.session_id === "cx").tool, "codex");
+      assert.equal(bodies.find((b) => b.data.session_id === "ag").tool, "antigravity");
+      assert.equal("tool" in bodies.find((b) => b.data.session_id === "zz"), false);
+      assert.equal("tool" in bodies.find((b) => b.data.session_id === "cc"), false);
+    } finally {
+      server.close();
+    }
+  });
+
   it("exits promptly when no dashboard is listening (connection refused)", async () => {
     // Grab a port then close it so nothing is listening there.
     const { server, port } = await startMockServer({ responseDelayMs: 0 });