P1a: material import, sixteen faces, sample engine and quarry

docs/PROTOCOL.md

@@ -91,3 +91,58 @@ The browser sets `binaryType = "arraybuffer"` and reads a `DataView`. The frame
 - Project/asset commands.
 - Agent tools and MCP.
 - Per-client cursors or collaboration.
+
+
+## P1a additions
+
+The protocol remains version 1; the additions are backward-compatible for the P0 surface (unknown fields are ignored).
+
+### Cores
+
+```json
+{
+  "type": "import_core",
+  "id": 100,
+  "name": "clicks-01.wav",
+  "seal": "found"
+}
+```
+
+The next binary frame from the client is the encoded audio. The daemon answers with:
+
+```json
+{"type":"imported","id":100,"core":{
+  "id":"core-f298c4956d","name":"clicks-01","seal":"found",
+  "sample_rate":48000,"duration_sec":2.6,
+  "faces":[{"index":0,"rank":9,"start_sec":0.0,"end_sec":0.14,"rms":0.14}],
+  "peaks":[0.0,0.32,...]
+}}
+```
+
+A snapshot follows and is broadcast to every client. `state.cores` carries the same summaries.
+
+### Pattern rows
+
+```json
+{"vein":"bass","face":{"core":"core-f298c4956d","face":10},"velocities":[112,0,...]}
+```
+
+`face: null` means the procedural voice for that vein.
+
+### Commands
+
+| command | args | journal |
+|---|---|---|
+| `strike_face` | `core`, `face`, `velocity` 0..1 | no |
+| `set_pattern_step` | `row` 0..4, `step` 0..15, `velocity` 0..127 | yes |
+| `set_pattern_face` | `row`, `core`, `face` | yes |
+
+Events: `pattern_step`, `pattern_face`, `face_struck`.
+
+### Import semantics
+
+- The import header must arrive immediately before the binary payload on the same connection.
+- The daemon decodes in a blocking task; the meter stream and other clients continue.
+- The archive id is a content hash prefix (`core-` + 10 hex); the same bytes get the same id.
+- The import is journaled on the session as `import_core` (journal-only; clients cannot send it as a command).
+- If the file cannot be decoded or is too short, the requester receives `error` with the import id.