Docs: add nodes overview

docs/nodes.md

@@ -0,0 +1,76 @@
+---
+summary: "Nodes: pairing, capabilities (canvas/camera), and the CLI helpers for screenshots + clips"
+read_when:
+  - Pairing iOS/Android nodes to a gateway
+  - Using node canvas/camera for agent context
+  - Adding new node commands or CLI helpers
+---
+
+# Nodes
+
+A **node** is a companion device (iOS/Android today) that connects to the Gateway over the **Bridge** and exposes a small command surface (e.g. `canvas.*`, `camera.*`) via `node.invoke`.
+
+## Pairing + status
+
+Pairing is gateway-owned and approval-based. See `docs/gateway/pairing.md` for the full flow.
+
+Quick CLI:
+
+```bash
+clawdis nodes pending
+clawdis nodes approve <requestId>
+clawdis nodes reject <requestId>
+clawdis nodes status
+clawdis nodes describe --node <idOrNameOrIp>
+```
+
+## Invoking commands
+
+Low-level (raw RPC):
+
+```bash
+clawdis nodes invoke --node <idOrNameOrIp> --command canvas.eval --params '{"javaScript":"location.href"}'
+```
+
+Higher-level helpers exist for the common “give the agent a MEDIA attachment” workflows.
+
+## Screenshots (canvas snapshots)
+
+If the node is showing the Canvas (WebView), `canvas.snapshot` returns `{ format, base64 }`.
+
+CLI helper (writes to a temp file and prints `MEDIA:<path>`):
+
+```bash
+clawdis nodes canvas snapshot --node <idOrNameOrIp> --format png
+clawdis nodes canvas snapshot --node <idOrNameOrIp> --format jpg --max-width 1200 --quality 0.9
+```
+
+## Photos + videos (node camera)
+
+Photos (`jpg`):
+
+```bash
+clawdis nodes camera snap --node <idOrNameOrIp>            # default: both facings (2 MEDIA lines)
+clawdis nodes camera snap --node <idOrNameOrIp> --facing front
+```
+
+Video clips (`mp4`):
+
+```bash
+clawdis nodes camera clip --node <idOrNameOrIp> --duration 10s
+clawdis nodes camera clip --node <idOrNameOrIp> --duration 3000 --no-audio
+```
+
+Notes:
+- The node must be **foregrounded** for `canvas.*` and `camera.*` (background calls return `NODE_BACKGROUND_UNAVAILABLE`).
+- Clip duration is clamped (currently `<= 60s`) to avoid oversized base64 payloads.
+- Android will prompt for `CAMERA`/`RECORD_AUDIO` permissions when possible; denied permissions fail with `*_PERMISSION_REQUIRED`.
+
+## Where to look in code
+
+- CLI wiring: `src/cli/nodes-cli.ts`
+- Canvas snapshot decoding/temp paths: `src/cli/nodes-canvas.ts`
+- Duration parsing for CLI: `src/cli/parse-duration.ts`
+- iOS node commands: `apps/ios/Sources/Model/NodeAppModel.swift`
+- Android node commands: `apps/android/app/src/main/java/com/steipete/clawdis/node/node/*`
+