Stable public release. API is frozen.

Changed #

• Version aligned with the rest of the super_cache family.
• Documentation improvements across all public symbols.

Added #

• DiskCache<K,V> — persistent file-per-entry cache:
  • Each entry stored as {keyHash}.dat (value bytes) + {keyHash}.meta (JSON sidecar with TTL and SHA-256 checksum).
  • SHA-256 integrity verification on every read; corrupted entries are treated as a cache miss and deleted automatically.
  • Write-back buffer: put is non-blocking. The value is immediately readable from the in-memory buffer while the disk write is queued.
  • Sequential write queue via chained futures — writes are serialised and the queue is fully drained by dispose().
  • Optional gzip compression (compress: true).
  • FIFO eviction when maxEntries (default 500) is exceeded.
  • Background TTL sweep timer (configurable sweepInterval).
  • initialize() scans the cache directory for existing entries so previously persisted data is available across app restarts.
• JsonCacheCodec<V> — serialises V via JSON (Map<String, dynamic> round-trip through fromJson/toJson functions).
• StringCacheCodec — UTF-8 codec for plain String values.