Add the OpenRouter catalog module

README.md

@@ -1,2 +1,30 @@
-# promptkit-backend-openrouter
+# Promptkit OpenRouter Catalog
 
+This repository publishes immutable OpenRouter catalog assets for Promptkit.
+It supplies catalog data only; it does not implement provider behavior, load
+credentials, or make network requests.
+
+Promptkit owns catalog parsing, validation, runtime behavior, credential
+handling, and consumer documentation. This module owns the OpenRouter backend
+manifest and its maintained profile data. Consumers should use versions chosen
+by their Promptkit release rather than treating this module as a standalone
+runtime integration.
+
+The profile assets originated in Promptkit. Their copyright holder has
+intentionally authorized their distribution in this repository under its
+LGPL-3.0 terms; this is a deliberate relicensing decision, not an automatic
+consequence of extracting a dependency.
+
+## Compatibility
+
+Catalog IDs are stable. New profiles are additive. Corrections are released as
+compatible catalog updates when they preserve the profile contract; deprecated
+profiles are announced before removal in a compatible-major release. Manifest
+schema changes follow semantic-version compatibility rules and retain support
+for compatible published catalog versions.
+
+## Validation and releases
+
+Run the offline Go tests, race tests, vet, build, formatting, hygiene, and
+module-resolution checks before release. The complete source-only release
+procedure is in [docs/release.md](docs/release.md).