The struct fc_slot was defined only in slot.c, making it an incomplete type
in slot.h. The inline accessor functions (fc_slot_id, fc_slot_header, etc.)
in slot.h could not compile because they referenced incomplete struct
members. The compiler fell back to implicit int return type, truncating
64-bit pointers to 32 bits, causing SIGSEGV in registry_add() when
strncpy received a truncated slot_id pointer.
Fix: move the struct definition to slot.h and add proper function
declarations for the accessors (definitions stay in slot.c).
- services/framecache/: new standalone container
- slot.h/slot.c: shm ring buffer (120 frames, FC_MAGIC header, atomic
write_cursor, POSIX semaphore per slot)
- registry.h/registry.c: in-memory slot registry + /dev/shm/framecache/
registry.json persistence
- framecache.c: HTTP API server (libmicrohttpd, port 7435)
POST /slots, GET /slots, GET /slots/:id, DELETE /slots/:id, GET /health
- fc_client.h/fc_client.c: consumer library — fc_consumer_open/read/close
with per-consumer cursor, timeout via sem_timedwait, automatic skip+count
when consumer falls behind writer by > ring_depth frames
- fc_test_consumer.c: dev utility to attach to any slot and print fps/stats
- CMakeLists.txt: framecache server + fc_client static lib + test consumer
- Dockerfile: builder + slim runtime stages
- docker-compose.worker.yml: add framecache service (profile: capture,
ipc: host, shm_size from FC_SHM_SIZE_GB env var, healthcheck)
- .env.example: document FC_SHM_SIZE_GB with per-node guidance
