chore(release): regenerate openapi.json for 0.8.1

The 0.8.1 version bump (6c1e6ad) bumped Cargo.toml but not the generated
OpenAPI doc, leaving info.version stale at 0.8.0. Regenerated — version
string only, no API surface change.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

api/openapi.json

@@ -10,7 +10,7 @@
       "name": "MIT OR Apache-2.0",
       "identifier": "MIT OR Apache-2.0"
     },
-    "version": "0.8.0"
+    "version": "0.8.1"
   },
   "paths": {
     "/api/v1/clients": {