feat: libraries and scanning — exclusions, links, missing tracks, lifecycle and watching (RFC-021)

.env.example

@@ -52,6 +52,14 @@ WAVEFLOW_STREAM_TICKET_TTL_SECS=3600
 # remain available. Extraction is parallel, SQLite writes stay serialized.
 WAVEFLOW_SCAN_INTERVAL_SECS=21600
 WAVEFLOW_SCAN_PARALLELISM=4
+# Watch library folders and scan a library once its changes have been quiet
+# for the delay. Unreliable on network mounts; the interval above stays as the
+# safety net (RFC-021).
+WAVEFLOW_WATCH=true
+WAVEFLOW_WATCH_DELAY_SECS=10
+# Purge tracks whose file has been missing for longer than this many days.
+# 0 never purges on its own; a purge is not reversible.
+WAVEFLOW_UNAVAILABLE_RETENTION_DAYS=0
 
 # FFmpeg and ffprobe are mandatory from M2 onward. Override these when the
 # executables are not discoverable through PATH.

Cargo.toml

@@ -39,13 +39,22 @@ encoding_rs = "0.8.42"
 futures-util = "0.3"
 hex = "0.4"
 ipnet = "2"
+# `.waveflowignore` (RFC-021 decision 1): gitignore rules through the matcher
+# ripgrep uses. Only its `gitignore` module is used, beside the `walkdir` walk
+# the scanner already has; `globset` and `walkdir` it builds on are in the
+# tree already.
+ignore = "0.4"
 lofty = "0.25"
 # TTML lyrics uploads (RFC-012 decision 6). Already in the lock file through
 # the artwork renderer; named here because the server now parses XML itself.
 # Its default options refuse a DTD, which is what keeps entities out.
 roxmltree = "0.21"
 libc = "0.2"
 md-5 = "0.11"
+# The library watcher (RFC-021 decision 6). Default features only, which is the
+# FSEvents backend on macOS and nothing else: inotify on Linux and
+# ReadDirectoryChangesW on Windows need no feature.
+notify = "8"
 # Already in the tree through `url`; declared because `playlist_file` reads
 # percent escapes out of playlist entries and a transitive dependency is not a
 # promise.