metadata: add .github/metadata.yaml draft (#1)

* metadata: add .github/metadata.yaml draft

Generated draft for review. Class: L3-foundation-or-other.

See Skills/github-repository for the standard; replace any TODO entries
with real values before merging.

* metadata: triaged

---------

Co-authored-by: swift-institute-bot <swift-institute-bot@users.noreply.github.com>

Author: swift-institute-bot[bot]

.github/metadata.yaml

@@ -0,0 +1,7 @@
+# .github/metadata.yaml
+# Triaged by AI-assisted bulk pass (2026-04-29).
+description: "YAML for Swift."
+topics:
+  - foundations
+  - yaml
+homepage: "https://swift-institute.org"