Slice 1 of M7 #352 added Server.DataDir but left it un-populated —
the playlist cover-collage writer would have used "" as the relative
path root in production, writing to the current working directory.
- Add Storage.DataDir to Config (yaml: storage.data_dir, env:
SMARTMUSIC_STORAGE_DATA_DIR), defaulting to "./data".
- server.New takes the data dir as a parameter; main.go threads it.
- main.go MkdirAll's the directory at startup so the playlist cover
writer doesn't fail on first use with a missing parent.
- config.example.yaml documents the new section.
Existing internal/server/server_test.go constructs Server directly
without server.New, so no test fixture changes needed for that file.
Validates seed_track + optional limit (default cfg.Recommendation.RadioSize,
clamped to RadioSizeMax). Calls recommendation.LoadCandidates +
recommendation.Shuffle. Prepends seed to result. Server seeds a
math/rand source at startup; handlers package threads that as a
func() float64 so tests inject deterministic RNGs.
Mount + server.New gain a RecommendationConfig parameter.
Discriminated-union JSON over three event types: play_started,
play_ended, play_skipped. Auth via existing RequireUser. play_started
returns play_event_id + session_id; the other two return { ok: true }.
Validates ownership: play_ended/play_skipped on another user's row
returns 403. Mount signature now takes EventsConfig and constructs
the playevents.Writer; server.New propagates it through.
Parses --config / SMARTMUSIC_CONFIG, loads YAML config with env overlay,
initializes slog, starts the chi HTTP server, and shuts down cleanly on
SIGINT/SIGTERM.
bvandeusen