feat(db): migrate from lowdb to SQLite with repos pattern

- Add modular DB layer (adapters, migrations, repos, helpers)
- Replace localDb/usageDb/requestDetailsDb monoliths with repos
- Add Tailscale tunnel integration & status check API
- Add /api/cli-tools/all-statuses aggregated endpoint
- Add settingsStore (Zustand) and mitm/dbReader
- Add DB unit tests (benchmark, concurrent, migration, vs-lowdb)

src/mitm/dbReader.js

@@ -0,0 +1,49 @@
+// CJS reader for MITM standalone process. Reads SQLite mitmAlias scope.
+// Falls back to legacy db.json or db.json.migrated if SQLite unavailable.
+const fs = require("fs");
+const path = require("path");
+const { DATA_DIR } = require("./paths");
+
+const DB_FILE = path.join(DATA_DIR, "db", "data.sqlite");
+const LEGACY_JSON = path.join(DATA_DIR, "db.json");
+const LEGACY_MIGRATED = path.join(DATA_DIR, "db.json.migrated");
+
+let sqliteDb = null;
+let sqliteFailed = false;
+
+function trySqlite() {
+  if (sqliteDb) return sqliteDb;
+  if (sqliteFailed) return null;
+  try {
+    if (!fs.existsSync(DB_FILE)) return null;
+    const Database = require("better-sqlite3");
+    sqliteDb = new Database(DB_FILE, { readonly: true, fileMustExist: true });
+    return sqliteDb;
+  } catch {
+    sqliteFailed = true;
+    return null;
+  }
+}
+
+function readLegacyJson() {
+  for (const file of [LEGACY_JSON, LEGACY_MIGRATED]) {
+    if (!fs.existsSync(file)) continue;
+    try { return JSON.parse(fs.readFileSync(file, "utf-8")); } catch {}
+  }
+  return null;
+}
+
+function getMitmAlias(toolName) {
+  const db = trySqlite();
+  if (db) {
+    try {
+      const row = db.prepare(`SELECT value FROM kv WHERE scope = 'mitmAlias' AND key = ?`).get(toolName);
+      if (row) return JSON.parse(row.value);
+    } catch {}
+  }
+  // Fallback to legacy JSON
+  const legacy = readLegacyJson();
+  return legacy?.mitmAlias?.[toolName] || null;
+}
+
+module.exports = { getMitmAlias };