feat: api key authentication (#291)

Co-authored-by: Elias Schneider <login@eliasschneider.com>

backend/resources/migrations/sqlite/20250302220732_api_key_auth.up.sql

@@ -0,0 +1,12 @@
+CREATE TABLE api_keys (
+    id TEXT PRIMARY KEY,
+    name TEXT NOT NULL,
+    key TEXT NOT NULL UNIQUE,
+    description TEXT,
+    expires_at DATETIME NOT NULL,
+    last_used_at DATETIME,
+    created_at DATETIME,
+    user_id TEXT REFERENCES users(id) ON DELETE CASCADE
+);
+
+CREATE INDEX idx_api_keys_key ON api_keys(key);