Feat: add a new agent: Google Anti Gravity (#1220)

* Add support for Antigravity (agy) agent

* fix a few things after gemini code update

* Fix missed merge conflicts

* As PR states it is IDE integration setting requires_cli to 'False'

---------

Co-authored-by: Manfred Riem <manfred.riem@microsoft.com>

src/specify_cli/__init__.py

@@ -220,6 +220,12 @@ AGENT_CONFIG = {
         "install_url": "https://github.com/ovh/shai",
         "requires_cli": True,
     },
+    "agy": {
+        "name": "Antigravity",
+        "folder": ".agent/",
+        "install_url": None,  # IDE-based
+        "requires_cli": False,
+    },
     "bob": {
         "name": "IBM Bob",
         "folder": ".bob/",
@@ -980,7 +986,7 @@ def ensure_constitution_from_template(project_path: Path, tracker: StepTracker |
 @app.command()
 def init(
     project_name: str = typer.Argument(None, help="Name for your new project directory (optional if using --here, or use '.' for current directory)"),
-    ai_assistant: str = typer.Option(None, "--ai", help="AI assistant to use: claude, gemini, copilot, cursor-agent, qwen, opencode, codex, windsurf, kilocode, auggie, codebuddy, amp, shai, q, bob, or qoder "),
+    ai_assistant: str = typer.Option(None, "--ai", help="AI assistant to use: claude, gemini, copilot, cursor-agent, qwen, opencode, codex, windsurf, kilocode, auggie, codebuddy, amp, shai, q, agy, bob, or qoder "),
     script_type: str = typer.Option(None, "--script", help="Script type to use: sh or ps"),
     ignore_agent_tools: bool = typer.Option(False, "--ignore-agent-tools", help="Skip checks for AI agent tools like Claude Code"),
     no_git: bool = typer.Option(False, "--no-git", help="Skip git repository initialization"),