Switch to SQLite-backed session storage, cleanup third-party dependencies, and refine CSP for restricted external assets.

src/db/schema.js

@@ -241,6 +241,10 @@ export function initializeSchema(db) {
 }
 
 export function runMigrations(db, {dropLegacyChats = true} = {}) {
+    db.exec(`CREATE TABLE IF NOT EXISTS schema_migrations (
+        version INTEGER PRIMARY KEY,
+        applied_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP
+    )`);
     db.exec(`CREATE TABLE IF NOT EXISTS chat_message_versions (
         id INTEGER PRIMARY KEY AUTOINCREMENT,
         message_id INTEGER NOT NULL REFERENCES chat_messages(id) ON DELETE CASCADE,
@@ -328,6 +332,12 @@ export function runMigrations(db, {dropLegacyChats = true} = {}) {
     ensureColumn("chat_sessions", chatSessionColumns, "system_instruction", "ALTER TABLE chat_sessions ADD COLUMN system_instruction TEXT");
     db.prepare("UPDATE chat_sessions SET is_pinned = 0 WHERE is_pinned IS NULL").run();
     db.prepare("UPDATE chat_sessions SET context_summary_message_id = 0 WHERE context_summary_message_id IS NULL").run();
+    db.exec(`
+        CREATE INDEX IF NOT EXISTS chat_sessions_owner_updated ON chat_sessions(username, updated_at DESC, id DESC);
+        CREATE INDEX IF NOT EXISTS chat_sessions_owner_archived_pinned ON chat_sessions(username, archived_at, is_pinned, updated_at DESC);
+        CREATE INDEX IF NOT EXISTS chat_messages_chat_created ON chat_messages(chat_id, created_at, id);
+        CREATE INDEX IF NOT EXISTS chat_memories_owner_chat ON chat_memories(username, chat_id, updated_at DESC);
+    `);
     if (!hadParentMessageId) {
         db.exec(`
             WITH ordered AS (
@@ -458,6 +468,7 @@ export function runMigrations(db, {dropLegacyChats = true} = {}) {
 
     const legacyChatsExist = db.prepare("SELECT name FROM sqlite_master WHERE type = 'table' AND name = 'chats'").get();
     if (!legacyChatsExist) {
+        db.prepare("INSERT OR IGNORE INTO schema_migrations(version) VALUES (?)").run(1);
         return;
     }
 
@@ -490,4 +501,5 @@ export function runMigrations(db, {dropLegacyChats = true} = {}) {
     if (dropLegacyChats) {
         db.prepare("DROP TABLE chats").run();
     }
+    db.prepare("INSERT OR IGNORE INTO schema_migrations(version) VALUES (?)").run(1);
 }