feat(release): add generation workflow

Add a guarded mobile release skill that synchronizes public versions, writes on-brand notes, verifies signed iOS and Android artifacts, and tags the verified release commit.

.codex/skills/generate-release/agents/openai.yaml

@@ -0,0 +1,4 @@
+interface:
+  display_name: "Generate Release"
+  short_description: "Bump, build, note, and tag Sauci releases"
+  default_prompt: "Use $generate-release to create the next signed Sauci mobile release for iOS and Android."