feat(init): deprecate --no-git flag, gate deprecations at v0.10.0

- Add deprecation warning when --no-git is used on specify init
- Update --ai deprecation gate from 1.0.0 to 0.10.0
- Update test expectation for the new version gate

Closes #2167

Author: mnriem

src/specify_cli/__init__.py

@@ -127,7 +127,7 @@ def _build_ai_deprecation_warning(
         ai_commands_dir=ai_commands_dir,
     )
     return (
-        "[bold]--ai[/bold] is deprecated and will no longer be available in version 1.0.0 or later.\n\n"
+        "[bold]--ai[/bold] is deprecated and will no longer be available in version 0.10.0 or later.\n\n"
         f"Use [bold]{replacement}[/bold] instead."
     )
 
@@ -1088,6 +1088,13 @@ def init(
                 'use [bold]--integration generic --integration-options="--commands-dir <dir>"[/bold] instead.[/dim]'
             )
 
+    if no_git:
+        console.print(
+            "[yellow]⚠️  --no-git is deprecated and will be removed in v0.10.0.[/yellow]\n"
+            "[yellow]The git extension will no longer be enabled by default "
+            "— use --extension git to opt in.[/yellow]"
+        )
+
     if project_name == ".":
         here = True
         project_name = None  # Clear project_name to use existing validation logic

tests/integrations/test_cli.py

@@ -112,7 +112,7 @@ def test_ai_emits_deprecation_warning_with_integration_replacement(self, tmp_pat
         assert "--ai" in normalized_output
         assert "deprecated" in normalized_output
         assert "no longer be available" in normalized_output
-        assert "1.0.0" in normalized_output
+        assert "0.10.0" in normalized_output
         assert "--integration copilot" in normalized_output
         assert normalized_output.index("Deprecation Warning") < normalized_output.index("Next Steps")
         assert (project / ".github" / "agents" / "speckit.plan.agent.md").exists()