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/openapi-extra/override-core.js

@@ -401,6 +401,12 @@ const paths = {
         "the normalized row that was just inserted (`session_id`, `agent_id`, `event_type`, " +
         "`tool_name`, `summary`, `created_at`). Ingestion is designed to be fail-safe and " +
         "non-blocking for the hook caller.\n\n" +
+        "The optional `tool` (`codex`, `antigravity`; anything else is `claude`) names the " +
+        "CLI that sent the hook. A Codex or agy hook is mapped onto the same hook types " +
+        "first (a Codex PermissionRequest becomes a Notification, an Interrupt a Stop; an " +
+        "agy turn's first PreInvocation a UserPromptSubmit), and one that maps to nothing " +
+        "is answered `{ ok: true, ignored: true }`. A hook delivered twice is answered " +
+        "`{ ok: true, duplicate: true }` and stored once.\n\n" +
         "Validation failures return HTTP 400 with an `ErrorResponse` body " +
         "(`{ error: { code, message } }`): `INVALID_INPUT` when `hook_type` or `data` is " +
         "missing, and `MISSING_SESSION` when `data.session_id` is absent.",