professionalize repo for public release

- rename ctcloud -> bucketeer everywhere (cmd/bucketeer, binary, compose service)
- group brand assets under assets/ (light/dark logo + UI screenshot)
- move long-form docs under docs/ (ARCHITECTURE, DESIGN, GOAL) and add
  docs/SKILL.md: how an agent queries/audits a running instance and answers
  user questions from the API and PostgreSQL
- README: large logo (light/dark picture) and UI screenshot, repository layout
- .gitignore: /bucketeer, .env, pgdata, build/test artifacts, OS junk
- .dockerignore: keep brand/docs/markdown out of the build context

internal/store/state.go

@@ -131,7 +131,7 @@ func (s *Store) RemoveSTH(ctx context.Context, logID monitor.LogID, sth *cttypes
 	return err
 }
 
-// StoreIssuer and LoadIssuer are no-ops. ctcloud's identifier sink bypasses
+// StoreIssuer and LoadIssuer are no-ops. bucketeer's identifier sink bypasses
 // certificate-chain retrieval entirely, so the issuer cache is never consulted;
 // keeping it empty also satisfies the "no certificate contents in the state
 // store" requirement. The Go runtime cache handles any incidental calls.
@@ -170,7 +170,7 @@ func (s *Store) NotifyError(ctx context.Context, ctlog *loglist.Log, notifyErr e
 	return nil
 }
 
-// GetErrors returns the recent CT errors. ctcloud keeps only aggregate counters.
+// GetErrors returns the recent CT errors. bucketeer keeps only aggregate counters.
 func (s *Store) GetErrors(ctx context.Context, ctlog *loglist.Log, count int) (string, error) {
 	return "", nil
 }

internal/store/store.go

@@ -17,7 +17,7 @@ import (
 	"tea.karlcom.de/karl/bucketeer/migrations"
 )
 
-// Store wraps a pgx pool with the operations ctcloud needs.
+// Store wraps a pgx pool with the operations bucketeer needs.
 type Store struct {
 	pool    *pgxpool.Pool
 	metrics *metrics.Metrics