deploy: main@3f5fd0f (works + reading + passage/multi-span notes; superset of f1c0d35)

deploy: reader-access security hardening (feature/audiobook@06a5ed8)

deploy: /audio/voices per-book voice status + Supertonic provider

deploy: audiobook subsystem + encode int16 fix + R2 page fast-path + costs breakdown + query-run flow