fix: restore alias compatibility for community extensions (#2110) (#2125)

Relax alias validation in _collect_manifest_command_names() to only
enforce the 3-part speckit.{ext}.{cmd} pattern on primary command
names. Aliases retain type and duplicate checking but are otherwise
free-form, restoring pre-#1994 behavior.

This unblocks community extensions (e.g. spec-kit-verify) that use
2-part aliases like 'speckit.verify'.

Fixes #2110

src/specify_cli/extensions.py

@@ -523,10 +523,11 @@ class ExtensionManager:
         """Collect command and alias names declared by a manifest.
 
         Performs install-time validation for extension-specific constraints:
-        - commands and aliases must use the canonical `speckit.{extension}.{command}` shape
+        - primary commands must use the canonical `speckit.{extension}.{command}` shape
-        - commands and aliases must use this extension's namespace
+        - primary commands must use this extension's namespace
         - command namespaces must not shadow core commands
         - duplicate command/alias names inside one manifest are rejected
+        - aliases are validated for type and uniqueness only (no pattern enforcement)
 
         Args:
             manifest: Parsed extension manifest
@@ -563,6 +564,9 @@ class ExtensionManager:
                         f"{kind.capitalize()} for command '{primary_name}' must be a string"
                     )
 
+                # Enforce canonical pattern only for primary command names;
+                # aliases are free-form to preserve community extension compat.
+                if kind == "command":
                     match = EXTENSION_COMMAND_NAME_PATTERN.match(name)
                     if match is None:
                         raise ValidationError(

tests/test_extensions.py

@@ -686,8 +686,8 @@ class TestExtensionManager:
         with pytest.raises(ValidationError, match="conflicts with core command namespace"):
             manager.install_from_directory(ext_dir, "0.1.0", register_commands=False)
 
-    def test_install_rejects_alias_without_extension_namespace(self, temp_dir, project_dir):
+    def test_install_accepts_short_alias(self, temp_dir, project_dir):
-        """Install should reject legacy short aliases that can shadow core commands."""
+        """Install should accept legacy short aliases for community extension compat."""
         import yaml
 
         ext_dir = temp_dir / "alias-shortcut"
@@ -718,7 +718,7 @@ class TestExtensionManager:
         (ext_dir / "commands" / "cmd.md").write_text("---\ndescription: Test\n---\n\nBody")
 
         manager = ExtensionManager(project_dir)
-        with pytest.raises(ValidationError, match="Invalid alias 'speckit.shortcut'"):
+        # Should not raise — short aliases are allowed
         manager.install_from_directory(ext_dir, "0.1.0", register_commands=False)
 
     def test_install_rejects_namespace_squatting(self, temp_dir, project_dir):