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/lib/claude-home.js

@@ -273,55 +273,31 @@ function findSubagentTranscriptPath(sessionId, agentId, runId = null) {
 }
 
 /**
- * Update CLAUDE_HOME at runtime. Updates process.env so getClaudeHome()
- * immediately returns the new value, and persists to .env file.
- * Returns the resolved absolute path.
+ * Update CLAUDE_HOME at runtime: `process.env` changes at once and the value
+ * persists to the settings file (`settings-env.js` — outside the repo, which a
+ * plugin update replaces, and outside CLAUDE_HOME). The path passes the shared
+ * `validateHomeDir` guard, which refuses anything that is or contains the
+ * user's home (`EBADHOME`).
+ *
+ * The data dir is derived from CLAUDE_HOME, so the first change pins the one
+ * in use as DASHBOARD_DATA_DIR (process + settings file) unless something
+ * already sets it: otherwise the next start would open an EMPTY database under
+ * the new home, and the plugin bootstrap and CLI — which never read the
+ * settings file — would disagree with the server about where its runtime is.
+ * The discovery file (`.agenthub.json`, server-info.js) is NOT pinned: it
+ * follows CLAUDE_HOME, so hooks and the CLI running under the default home
+ * find a dashboard on a non-default port only if they share its CLAUDE_HOME.
+ *
+ * @returns {string} the resolved absolute path.
  */
 function setClaudeHome(newPath) {
-  const resolved = newPath.replace(/^~(?=\/)/, os.homedir());
-  if (!path.isAbsolute(resolved)) {
-    throw new Error("CLAUDE_HOME must be an absolute path");
-  }
-  if (!fs.existsSync(resolved)) {
-    throw new Error(`Directory does not exist: ${resolved}`);
-  }
-  const stat = fs.statSync(resolved);
-  if (!stat.isDirectory()) {
-    throw new Error(`Not a directory: ${resolved}`);
-  }
-  process.env.CLAUDE_HOME = resolved;
-  writeEnvFile("CLAUDE_HOME", resolved);
+  const { validateHomeDir, applySetting } = require("./settings-env");
+  const resolved = validateHomeDir("CLAUDE_HOME", newPath);
+  if (!process.env.DASHBOARD_DATA_DIR) applySetting("DASHBOARD_DATA_DIR", getDataDir());
+  applySetting("CLAUDE_HOME", resolved);
   return resolved;
 }
 
-/**
- * Write or update a key=value line in the .env file.
- * Creates the file if it doesn't exist.
- */
-function writeEnvFile(key, value) {
-  const envPath = path.resolve(__dirname, "..", "..", ".env");
-  let lines = [];
-  if (fs.existsSync(envPath)) {
-    lines = fs.readFileSync(envPath, "utf8").split("\n");
-  }
-  let found = false;
-  for (let i = 0; i < lines.length; i++) {
-    const trimmed = lines[i].trim();
-    if (trimmed.startsWith(`${key}=`)) {
-      lines[i] = `${key}=${value}`;
-      found = true;
-      break;
-    }
-  }
-  if (!found) {
-    lines.push(`${key}=${value}`);
-  }
-  // Write atomically: write to temp file then rename to prevent corruption
-  const tempPath = envPath + ".tmp";
-  fs.writeFileSync(tempPath, lines.join("\n") + "\n", "utf8");
-  fs.renameSync(tempPath, envPath);
-}
-
 module.exports = {
   getClaudeHome,
   getProjectsDir,
@@ -337,5 +313,4 @@ module.exports = {
   findTranscriptPath,
   findSubagentTranscriptPath,
   setClaudeHome,
-  writeEnvFile,
 };