docs: record Opus/derived read-path streaming and index-only opus-status

CLAUDE.md

@@ -42,7 +42,7 @@ Server-side (SSR): Both clients point directly at DeepDrftAPI (server-to-server,
    - Root contains typed **MediaVaults** (Media, Image, Audio)
    - Each vault has a JSON `index` file listing entries + per-entry metadata
    - Entries are user-supplied strings sanitized to `[a-zA-Z0-9-]` + file extension
-   - Binary hierarchy (**read/load path**): `FileBinary` → `MediaBinary` (+ Extension/MIME) → `AudioBinary` (+ Duration/Bitrate) | `ImageBinary` (+ AspectRatio). The **write/store path** is streaming: audio processors return a `ProcessedAudio` plan (metadata + streamed `WriteToAsync` callback); `RegisterResourceStreamingAsync` / `MediaVault.AddEntryStreamingAsync` write bytes to a temp file then `File.Move` atomic-rename into place — the full `AudioBinary` buffer is never materialized on this path.
+   - Binary hierarchy (model shapes): `FileBinary` → `MediaBinary` (+ Extension/MIME) → `AudioBinary` (+ Duration/Bitrate) | `ImageBinary` (+ AspectRatio). **Non-delivery read path** (`LoadResourceAsync<AudioBinary>`) returns a full-buffer `AudioBinary` — still used for non-delivery operations (e.g., duration backfill). **Audio delivery path** streams via `GetEntryStreamAsync` (Opus artifact, `track-opus` vault) or `OpenAudioMediaStreamAsync` (lossless source, `tracks` vault) — a seekable, disk-backed `Stream` per request, never a whole-file `byte[]` (read-side OOM fix, parallel to the store-side). The **write/store path** is streaming: audio processors return a `ProcessedAudio` plan (metadata + streamed `WriteToAsync` callback); `RegisterResourceStreamingAsync` / `MediaVault.AddEntryStreamingAsync` write bytes to a temp file then `File.Move` atomic-rename into place — the full `AudioBinary` buffer is never materialized on this path.
    - **Error-handling philosophy**: public operations swallow exceptions and return `null`/`false` — callers must check return values, not catch.
 
 ## Key Architectural Decisions