feat: add the aegis-gitea-mcp setup command

Verifies the Gitea instance, token and scopes, registers or reuses the aegis-gitea-mcp OAuth app, generates missing secrets and writes a 0600 env file from the template. Prints client configs and deployment snippets without any secret value.

tests/test_setup_template.py

@@ -0,0 +1,12 @@
+"""The embedded env template must stay identical to ``.env.example``."""
+
+from __future__ import annotations
+
+from pathlib import Path
+
+from aegis_gitea_mcp.setup_template import ENV_TEMPLATE
+
+
+def test_embedded_template_matches_env_example() -> None:
+    example = Path(__file__).parent.parent / ".env.example"
+    assert example.read_text(encoding="utf-8") == ENV_TEMPLATE