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/routes/sessions.js

@@ -127,6 +127,9 @@ router.get("/", (req, res) => {
   const status = req.query.status;
   const q = typeof req.query.q === "string" ? req.query.q.trim() : "";
   const cwd = req.query.cwd;
+  // Which CLI's sessions (claude / codex / antigravity). Applied here, before
+  // the limit, so a busy Codex lane cannot push Claude rows out of a page.
+  const tool = typeof req.query.tool === "string" ? req.query.tool : "";
   const sortBy = req.query.sort_by || "time"; // "time", "duration", "price"
   const sortDesc = req.query.sort_desc !== "false";
 
@@ -146,6 +149,10 @@ router.get("/", (req, res) => {
     where.push("s.cwd = ?");
     params.push(cwd);
   }
+  if (tool) {
+    where.push("s.tool = ?");
+    params.push(tool);
+  }
   // Data-scope filter: restrict to sessions collected from a chosen set of
   // machines (local + any configured remote sources). Absent = all sources.
   const sourceFilter = sourceColumnClause(parseSources(req));