Refactor runner and installation scripts for improved functionality

- Removed the `--disable-hiprt` flag from the runner command, simplifying the rendering options for users.
- Updated the `jiggablend-runner` script and README to reflect the removal of the HIPRT control flag, enhancing clarity in usage instructions.
- Enhanced the installation script to provide clearer examples for running the jiggablend manager and runner, improving user experience during setup.
- Implemented a more robust GPU backend detection mechanism, allowing for better compatibility with various hardware configurations.

internal/database/migrations/000003_add_last_used_at.down.sql

@@ -0,0 +1,24 @@
+-- SQLite does not support DROP COLUMN directly; recreate the table without last_used_at.
+CREATE TABLE runner_api_keys_backup (
+	id INTEGER PRIMARY KEY AUTOINCREMENT,
+	key_prefix TEXT NOT NULL,
+	key_hash TEXT NOT NULL,
+	name TEXT NOT NULL,
+	description TEXT,
+	scope TEXT NOT NULL DEFAULT 'user',
+	is_active INTEGER NOT NULL DEFAULT 1,
+	created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
+	created_by INTEGER,
+	FOREIGN KEY (created_by) REFERENCES users(id),
+	UNIQUE(key_prefix)
+);
+
+INSERT INTO runner_api_keys_backup SELECT id, key_prefix, key_hash, name, description, scope, is_active, created_at, created_by FROM runner_api_keys;
+
+DROP TABLE runner_api_keys;
+
+ALTER TABLE runner_api_keys_backup RENAME TO runner_api_keys;
+
+CREATE INDEX idx_runner_api_keys_prefix ON runner_api_keys(key_prefix);
+CREATE INDEX idx_runner_api_keys_active ON runner_api_keys(is_active);
+CREATE INDEX idx_runner_api_keys_created_by ON runner_api_keys(created_by);

internal/database/migrations/000003_add_last_used_at.up.sql

@@ -0,0 +1 @@
+ALTER TABLE runner_api_keys ADD COLUMN last_used_at TIMESTAMP;