Add video upload, extraction progress, and reusable analysis sources

docs/architecture.md

@@ -570,10 +570,15 @@ addressing that answers questions about work not yet done.
 
 ```
 POST /api/analyses              {key, descriptor}        idempotent
+GET  /api/analyses/<key>        metadata + source block keys
+PUT  /api/analyses/<key>        link dense landmarks, mask, crops
 POST /api/blocks/missing        {keys} -> {missing}
 POST /api/blocks                {key, descriptor, data, state}
 GET  /api/blocks/<key>
 GET  /api/footage/<id>          the manifest, with a URL per frame
+POST /api/sources               multipart video upload
+POST /api/extractions           idempotent decode job
+GET  /api/extractions/<key>     job state and footage id
 ```
 
 **The server verifies, rather than trusting a name it was handed.** It recomputes
@@ -596,9 +601,9 @@ separately.
 fetched `manifest.json` and built `frames/0001.png` itself, which made the frame
 layout a shared secret between a shell script and a ClojureScript namespace. The
 manifest now carries a URL per frame, so the frames can live in the blob store —
-or, when wasm-ffmpeg extraction arrives, be uploaded into the same store by the
-app — and the client learns nothing new when that happens. The producer changes;
-the shape does not.
+or be produced by the app's video upload and server-side ffmpeg extraction. The
+upload path needs no `manifest.json` file: the server builds the footage response
+from the extracted frame records. The producer changes; the shape does not.
 
 **The document stores what a block IS, not what it holds.** A block's element type
 is in its own descriptor, which is the only place it is written down: an