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.

docs/DEPLOYMENT.md

@@ -251,10 +251,17 @@ DASHBOARD_ALLOWED_HOSTS=                # extra Host names (comma-sep) for a LAN
 # Database
 DASHBOARD_DB_PATH=/var/lib/agenthub/dashboard.db
 
-# Ingestion polls (0 disables either one)
+# Ingestion polls (0 disables any one of them)
 DASHBOARD_WORKFLOW_POLL_MS=12000        # Workflow-tool run journals
-DASHBOARD_CODEX_POLL_MS=15000           # Codex rollout journals → codex lane running/idle
+DASHBOARD_CODEX_POLL_MS=15000           # Codex rollout journals → codex lane running/idle + Codex sessions/tokens
 CODEX_HOME=                             # where Codex keeps sessions/ (default ~/.codex)
+DASHBOARD_ANTIGRAVITY_POLL_MS=15000     # agy conversation files → Antigravity sessions/tokens
+AGENTHUB_GEMINI_DIR=                    # where agy keeps its data (default ~/.gemini)
+
+# Pricing and saved settings
+AGENTHUB_PRICING_SYNC=                  # 0|false|off disables automatic pricing from LiteLLM (default on)
+AGENTHUB_SETTINGS_FILE=                 # where dashboard-saved settings persist (default ~/.config/agenthub/settings.env);
+                                        # load order: real env > the checkout's .env > this file
 
 # Logging
 LOG_LEVEL=info                         # debug | info | warn | error