fix: rename .traefik.yaml to .traefik.yml for catalog compliance

The Traefik Plugin Catalog requires the manifest file to be named
exactly .traefik.yml; .traefik.yaml is not recognized and would
silently block catalog imports.

Author: cmuench

.traefik.yaml .traefik.yml.traefik.yaml renamed to .traefik.yml

@@ -42,7 +42,7 @@ because the module path `query-to-header` is not a valid Go identifier):
     parameter (`Remove`), rewrites `req.URL.RawQuery`, then calls `next.ServeHTTP`.
 - **`query_to_header_test.go`** — table-style tests built around `httptest.NewRequest` /
   `httptest.NewRecorder`, asserting on header/query state observed inside a stub `next` handler.
-- **`.traefik.yaml`** — the plugin manifest required by the Traefik Plugin Catalog
+- **`.traefik.yml`** — the plugin manifest required by the Traefik Plugin Catalog
   (`displayName`, `type: middleware`, `import`, `summary`, `testData` used to validate the
   catalog example config matches `Config`'s JSON shape).
 
@@ -54,6 +54,23 @@ the version, commit, tag, and push (`github.release: false`, `npm.publish: false
 resulting `vX.Y.Z` tag triggers `.github/workflows/release.yml`, which runs `goreleaser` to
 actually publish the GitHub Release.
 
+## Traefik Plugin Catalog requirements
+
+The catalog (https://plugins.traefik.io) polls GitHub daily and imports repositories that meet
+all of these criteria — breaking any of them silently stops catalog updates:
+
+- Repository must not be a fork.
+- The `traefik-plugin` topic must be set on the GitHub repository.
+- `.traefik.yml` must exist at repo root with a valid `testData` property matching `Config`'s
+  JSON shape.
+- A valid `go.mod` must exist at repo root.
+- The plugin must be versioned via git tag (source is pulled from the Go module proxy, not a
+  branch).
+- Any package dependencies must be vendored and committed — moot here since this plugin has none.
+
+If the catalog's import fails, it opens an issue on this repo explaining the problem and pauses
+re-import attempts until that issue is closed.
+
 ## Conventions to preserve
 
 - Keep `New` and `CreateConfig` signatures exact — Traefik's plugin loader calls them by

AGENTS.md

@@ -125,7 +125,7 @@ middleware to fail to load (validated in `New`, at construction time, not per-re
 |--------------------------------|----------------------------------------------------------------------|
 | `query_to_header.go`          | Plugin implementation: `Config`, `CreateConfig`, `New`, `ServeHTTP`. |
 | `query_to_header_test.go`     | Unit tests using `httptest`.                                        |
-| `.traefik.yaml`                | Plugin manifest required by the Traefik Plugin Catalog.             |
+| `.traefik.yml`                | Plugin manifest required by the Traefik Plugin Catalog.             |
 | `go.mod`                       | No third-party dependencies — required for Yaegi compatibility.     |
 | `.golangci.yml`                | Lint configuration.                                                  |
 | `justfile`                     | `lint`, `test`, `vendor`, `clean` recipes (run with [`just`](https://just.systems)). |