feat(tui): add usage overlay and sidebar for displaying usage statistics and tasks

feat(tui): implement status bar with connection and turn state indicators
feat(tui): create workflow panel for agent status and progress visualization
feat(web): introduce web frontend interface with static file serving
feat(ws): add WebSocket interface for real-time communication and session management

apps/infrastructure/src/persistence/sqlite/database.rs

@@ -0,0 +1,88 @@
+//! SQLite database connection initialisation and schema migrations.
+
+use std::sync::{Arc, Mutex};
+
+/// A shared SQLite connection wrapped for thread-safe access.
+#[derive(Clone)]
+pub struct DbConn {
+    conn: Arc<Mutex<rusqlite::Connection>>,
+}
+
+impl DbConn {
+    /// Execute a closure with a reference to the underlying connection.
+    pub fn with<F, T>(&self, f: F) -> anyhow::Result<T>
+    where
+        F: FnOnce(&rusqlite::Connection) -> anyhow::Result<T>,
+    {
+        let conn = self
+            .conn
+            .lock()
+            .map_err(|e| anyhow::anyhow!("db lock poisoned: {e}"))?;
+        f(&conn)
+    }
+}
+
+const SCHEMA_SQL: &str = r#"
+CREATE TABLE IF NOT EXISTS sessions (
+    id          TEXT PRIMARY KEY,
+    created_at  INTEGER NOT NULL,
+    updated_at  INTEGER NOT NULL,
+    title       TEXT NOT NULL DEFAULT '',
+    model       TEXT NOT NULL DEFAULT '',
+    workspace_roots TEXT NOT NULL DEFAULT '[]',
+    message_count   INTEGER NOT NULL DEFAULT 0,
+    token_count     INTEGER NOT NULL DEFAULT 0,
+    archived    INTEGER NOT NULL DEFAULT 0,
+    summary     TEXT
+);
+
+CREATE TABLE IF NOT EXISTS settings (
+    id          INTEGER PRIMARY KEY CHECK (id = 1),
+    data        TEXT NOT NULL DEFAULT '{}',
+    updated_at  INTEGER NOT NULL
+);
+
+CREATE TABLE IF NOT EXISTS conversations (
+    session_id  TEXT PRIMARY KEY,
+    data        TEXT NOT NULL DEFAULT '{}',
+    updated_at  INTEGER NOT NULL
+);
+
+CREATE TABLE IF NOT EXISTS memories (
+    name        TEXT PRIMARY KEY,
+    data        TEXT NOT NULL DEFAULT '{}',
+    updated_at  INTEGER NOT NULL
+);
+
+CREATE TABLE IF NOT EXISTS edit_logs (
+    id          INTEGER PRIMARY KEY AUTOINCREMENT,
+    session_id  TEXT NOT NULL,
+    entry       TEXT NOT NULL,
+    created_at  INTEGER NOT NULL
+);
+
+CREATE INDEX IF NOT EXISTS idx_edit_logs_session
+    ON edit_logs (session_id);
+"#;
+
+/// Initialise a shared SQLite connection at the given path.
+pub fn init_db(db_path: &str) -> anyhow::Result<DbConn> {
+    let conn = rusqlite::Connection::open(db_path)
+        .map_err(|e| anyhow::anyhow!("failed to open SQLite database at '{db_path}': {e}"))?;
+
+    conn.execute_batch("PRAGMA journal_mode = WAL;")?;
+    conn.execute_batch("PRAGMA busy_timeout = 5000;")?;
+
+    Ok(DbConn {
+        conn: Arc::new(Mutex::new(conn)),
+    })
+}
+
+/// Run embedded SQL schema migrations.
+pub fn run_migrations(db: &DbConn) -> anyhow::Result<()> {
+    db.with(|conn| {
+        conn.execute_batch(SCHEMA_SQL)
+            .map_err(|e| anyhow::anyhow!("failed to execute database schema migrations: {e}"))
+    })?;
+    Ok(())
+}