refactor: restructure db logic and add import alias using tsc-alias

Note: the legacy githubTokensDb migration is not included in this commit.
It's used only in `agents.js` and will be removed in a future commit. We
will directly use credentials repository instead of github tokens repository.

server/src/shared/database/schema.ts

@@ -0,0 +1,90 @@
+const USER_TABLE_SCHEMA_SQL = `
+CREATE TABLE IF NOT EXISTS users (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    username TEXT UNIQUE NOT NULL,
+    password_hash TEXT NOT NULL,
+    created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
+    last_login DATETIME,
+    is_active BOOLEAN DEFAULT 1,
+    git_name TEXT,
+    git_email TEXT,
+    has_completed_onboarding BOOLEAN DEFAULT 0
+);
+`;
+
+export const API_KEYS_TABLE_SCHEMA_SQL = `
+CREATE TABLE IF NOT EXISTS api_keys (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    user_id INTEGER NOT NULL,
+    key_name TEXT NOT NULL,
+    api_key TEXT UNIQUE NOT NULL,
+    created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
+    last_used DATETIME,
+    is_active BOOLEAN DEFAULT 1,
+    FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
+);
+`;
+
+export const USER_CREDENTIALS_TABLE_SCHEMA_SQL = `
+CREATE TABLE IF NOT EXISTS user_credentials (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    user_id INTEGER NOT NULL,
+    credential_name TEXT NOT NULL,
+    credential_type TEXT NOT NULL, -- 'github_token', 'gitlab_token', 'bitbucket_token', etc.
+    credential_value TEXT NOT NULL,
+    description TEXT,
+    created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
+    is_active BOOLEAN DEFAULT 1,
+    FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
+);
+`;
+
+export const SESSION_NAMES_TABLE_SCHEMA_SQL = `
+CREATE TABLE IF NOT EXISTS session_names (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    session_id TEXT NOT NULL,
+    provider TEXT NOT NULL DEFAULT 'claude',
+    custom_name TEXT NOT NULL,
+    created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
+    updated_at DATETIME DEFAULT CURRENT_TIMESTAMP,
+    UNIQUE(session_id, provider)
+);
+`;
+
+export const APP_CONFIG_TABLE_SCHEMA_SQL = `
+CREATE TABLE IF NOT EXISTS app_config (
+    key TEXT PRIMARY KEY,
+    value TEXT NOT NULL,
+    created_at DATETIME DEFAULT CURRENT_TIMESTAMP
+);
+`;
+
+
+export const INIT_SCHEMA_SQL = `
+-- Initialize authentication database
+PRAGMA foreign_keys = ON;
+
+${USER_TABLE_SCHEMA_SQL}
+-- Indexes for performance for user lookups
+CREATE INDEX IF NOT EXISTS idx_users_username ON users(username);
+CREATE INDEX IF NOT EXISTS idx_users_active ON users(is_active);
+
+${API_KEYS_TABLE_SCHEMA_SQL}
+
+CREATE INDEX IF NOT EXISTS idx_api_keys_key ON api_keys(api_key);
+CREATE INDEX IF NOT EXISTS idx_api_keys_user_id ON api_keys(user_id);
+CREATE INDEX IF NOT EXISTS idx_api_keys_active ON api_keys(is_active);
+
+${USER_CREDENTIALS_TABLE_SCHEMA_SQL}
+
+CREATE INDEX IF NOT EXISTS idx_user_credentials_user_id ON user_credentials(user_id);
+CREATE INDEX IF NOT EXISTS idx_user_credentials_type ON user_credentials(credential_type);
+CREATE INDEX IF NOT EXISTS idx_user_credentials_active ON user_credentials(is_active);
+
+${SESSION_NAMES_TABLE_SCHEMA_SQL}
+
+CREATE INDEX IF NOT EXISTS idx_session_names_lookup ON session_names(session_id, provider);
+
+${APP_CONFIG_TABLE_SCHEMA_SQL}
+`;
+