feat(podcasts+ops): Apple launcher-scheme feeds + visible build stamp

Apple scheme normalization (follow-up to the Scribl discussion): Add
Feed accepts the launcher spellings podcast pages ship next to plain
RSS — itpc://, podcasts://, feed:// — and rewrites them to the https
feed URL they wrap (scheme match case-insensitive). http stays and the
guard still rejects it. Unit-pinned.

Build stamp (stale-container drift guard): the 2026-10-29 podcast
session lost an hour to a container running a build that predated the
feature. version.Commit rides ldflags from a GIT_COMMIT build arg; the
dev compose passes git rev-parse --short HEAD via the Makefile; the
app logs 'Bookhoard <ver> (commit <hash>)' at boot and /api/health
reports it — the UI and the repo can no longer silently diverge.

docker-compose.dev.yml

@@ -12,6 +12,8 @@ services:
     build:
       context: .
       dockerfile: ./Dockerfile
+      args:
+        GIT_COMMIT: ${GIT_COMMIT:-none}
 
   # Integration Tests - runs against containerized app and db (dev only)
   tests: