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.

cmd/server/main.go

@@ -10,6 +10,7 @@ import (
 	"bookhoard/internal/router"
 	"bookhoard/internal/services"
 	"bookhoard/internal/sync"
+	"bookhoard/internal/version"
 	"bookhoard/templates"
 	"context"
 	"log"
@@ -33,6 +34,7 @@ func (cv *CustomValidator) Validate(i interface{}) error {
 }
 
 func main() {
+	log.Printf("Bookhoard %s (commit %s) starting", version.Version, version.Commit)
 	cfg := config.LoadConfig()
 
 	dbPool, err := pgxpool.New(context.Background(), cfg.DatabaseURL())