ci(registry): enforce .json-only component submission files (#19)

Fail validation when any non-JSON file exists in components/registry/components and document the rule in the registry README so contributors understand CI expectations.

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: sfc-gh-bnisco

components/registry/README.md

@@ -72,6 +72,7 @@ Your JSON must conform to [`components/registry/schemas/component.schema.json`](
 
 The validator enforces a few “lint” rules to keep the registry stable:
 
+- **JSON-only directory**: every file in `components/registry/components/` must end with `.json` (placeholder files like `.gitkeep` will fail CI).
 - **Unique repo**: `links.github` must be unique across all submissions. If the same repo was already submitted, CI will fail.
 - **HTTPS only**: all URLs must be `https://` and must not use `javascript:`, `data:`, or `file:` schemes.
 - **Stable images** (`media.image`): must be a stable `https://` URL.

components/registry/components/.gitkeep

@@ -206,6 +206,21 @@ def validate_components(repo_root: Path) -> list[ValidationIssue]:
     validator = _get_validator(schema_path)
 
     issues: list[ValidationIssue] = []
+    for file_path in sorted(components_dir.iterdir()):
+        if not file_path.is_file():
+            continue
+        if file_path.suffix != ".json":
+            issues.append(
+                ValidationIssue(
+                    file=file_path,
+                    schema=schema_path,
+                    message=(
+                        "Invalid file extension in components directory. "
+                        "Source component files must end with `.json`."
+                    ),
+                    json_path=None,
+                )
+            )
     for json_file in sorted(components_dir.glob("*.json")):
         issues.extend(_validate_one(json_file, schema_path, validator))
     return issues