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 };

src/mitm/handlers/base.js

@@ -1,6 +1,6 @@
 const { log, err } = require("../logger");
 
-const DEFAULT_LOCAL_ROUTER = "http://localhost:20128";
+const DEFAULT_LOCAL_ROUTER = "http://127.0.0.1:20128";
 const ROUTER_BASE = String(process.env.MITM_ROUTER_BASE || DEFAULT_LOCAL_ROUTER)
   .trim()
   .replace(/\/+$/, "") || DEFAULT_LOCAL_ROUTER;

src/mitm/manager.js

@@ -16,7 +16,7 @@ const { isCertExpired } = require("./cert/rootCA");
 const { DATA_DIR, MITM_DIR } = require("./paths");
 const { log, err } = require("./logger");
 
-const DEFAULT_MITM_ROUTER_BASE = "http://localhost:20128";
+const DEFAULT_MITM_ROUTER_BASE = "http://127.0.0.1:20128";
 
 function shellQuoteSingle(str) {
   if (str == null || str === "") return "''";

src/mitm/server.js

@@ -8,8 +8,7 @@ const { log, err, dumpRequest, createResponseDumper } = require("./logger");
 const { TARGET_HOSTS, URL_PATTERNS, MODEL_SYNONYMS, getToolForHost } = require("./config");
 const { DATA_DIR, MITM_DIR } = require("./paths");
 const { getCertForDomain } = require("./cert/generate");
-
-const DB_FILE = path.join(DATA_DIR, "db.json");
+const { getMitmAlias } = require("./dbReader");
 const LOCAL_PORT = 443;
 const IS_WIN = process.platform === "win32";
 const ENABLE_FILE_LOG = true;
@@ -108,9 +107,7 @@ function extractModel(url, body) {
 function getMappedModel(tool, model) {
   if (!model) return null;
   try {
-    if (!fs.existsSync(DB_FILE)) return null;
-    const db = JSON.parse(fs.readFileSync(DB_FILE, "utf-8"));
-    const aliases = db.mitmAlias?.[tool];
+    const aliases = getMitmAlias(tool);
     if (!aliases) return null;
     // Normalize via synonym map (e.g., gemini-default → gemini-3-flash)
     const lookup = MODEL_SYNONYMS?.[tool]?.[model] || model;