feat: define canonical presence schema for Workshop (#265)

ADR-023: Specifies ~/.timmy/presence.json schema — the contract between
Timmy (writer) and the Workshop (reader).

- JSON v1 schema with liveness, current_focus, active_threads,
  recent_events, concerns, and mood fields
- 5-minute staleness threshold for liveness
- Capped arrays (20 events, 10 threads, 5 concerns)
- Versioned for forward compatibility
- Written as side effect of work, not a daemon

docs/adr/023-workshop-presence-schema.md

@@ -0,0 +1,166 @@
+# ADR-023: Workshop Presence Schema
+
+**Status:** Accepted
+**Date:** 2026-03-18
+**Issue:** #265
+**Epic:** #222 (The Workshop)
+
+## Context
+
+The Workshop renders Timmy as a living presence in a 3D world. It needs to
+know what Timmy is doing *right now* — his working memory, not his full
+identity or history. This schema defines the contract between Timmy (writer)
+and the Workshop (reader).
+
+Design principles:
+- **Working memory, not long-term memory.** Present tense only.
+- **Written as side effect of work.** Not a separate obligation.
+- **Liveness is mandatory.** Stale = "not home," shown honestly.
+- **Schema is the contract.** Keep it minimal and stable.
+
+## Decision
+
+### File Location
+
+`~/.timmy/presence.json`
+
+JSON chosen over YAML for predictable parsing by both Python and JavaScript
+(the Workshop frontend). The Workshop reads this file via the WebSocket
+bridge (#243) or polls it directly during development.
+
+### Schema (v1)
+
+```json
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "title": "Timmy Presence State",
+  "description": "Working memory surface for the Workshop renderer",
+  "type": "object",
+  "required": ["version", "liveness", "current_focus"],
+  "properties": {
+    "version": {
+      "type": "integer",
+      "const": 1,
+      "description": "Schema version for forward compatibility"
+    },
+    "liveness": {
+      "type": "string",
+      "format": "date-time",
+      "description": "ISO 8601 timestamp of last update. If stale (>5min), Timmy is not home."
+    },
+    "current_focus": {
+      "type": "string",
+      "description": "One sentence: what Timmy is doing right now. Empty string = idle."
+    },
+    "active_threads": {
+      "type": "array",
+      "maxItems": 10,
+      "description": "Current work items Timmy is tracking",
+      "items": {
+        "type": "object",
+        "required": ["type", "ref", "status"],
+        "properties": {
+          "type": {
+            "type": "string",
+            "enum": ["pr_review", "issue", "conversation", "research", "thinking"]
+          },
+          "ref": {
+            "type": "string",
+            "description": "Reference identifier (issue #, PR #, topic name)"
+          },
+          "status": {
+            "type": "string",
+            "enum": ["active", "idle", "blocked", "completed"]
+          }
+        }
+      }
+    },
+    "recent_events": {
+      "type": "array",
+      "maxItems": 20,
+      "description": "Recent events, newest first. Capped at 20.",
+      "items": {
+        "type": "object",
+        "required": ["timestamp", "event"],
+        "properties": {
+          "timestamp": {
+            "type": "string",
+            "format": "date-time"
+          },
+          "event": {
+            "type": "string",
+            "description": "Brief description of what happened"
+          }
+        }
+      }
+    },
+    "concerns": {
+      "type": "array",
+      "maxItems": 5,
+      "description": "Things Timmy is uncertain or worried about. Flat list, no severity.",
+      "items": {
+        "type": "string"
+      }
+    },
+    "mood": {
+      "type": "string",
+      "enum": ["focused", "exploring", "uncertain", "excited", "tired", "idle"],
+      "description": "Emotional texture for the Workshop to render. Optional."
+    }
+  }
+}
+```
+
+### Example
+
+```json
+{
+  "version": 1,
+  "liveness": "2026-03-18T21:47:12Z",
+  "current_focus": "Reviewing PR #267 — stream adapter for Gitea webhooks",
+  "active_threads": [
+    {"type": "pr_review", "ref": "#267", "status": "active"},
+    {"type": "issue", "ref": "#239", "status": "idle"},
+    {"type": "conversation", "ref": "hermes-consultation", "status": "idle"}
+  ],
+  "recent_events": [
+    {"timestamp": "2026-03-18T21:45:00Z", "event": "Completed PR review for #265"},
+    {"timestamp": "2026-03-18T21:30:00Z", "event": "Filed issue #268 — flaky test in sensory loop"}
+  ],
+  "concerns": [
+    "WebSocket reconnection logic feels brittle",
+    "Not sure the barks system handles uncertainty well yet"
+  ],
+  "mood": "focused"
+}
+```
+
+### Design Answers
+
+| Question | Answer |
+|---|---|
+| File format | JSON (predictable for JS + Python, no YAML parser needed in browser) |
+| recent_events cap | 20 entries max, oldest dropped |
+| concerns severity | Flat list, no priority. Keep it simple. |
+| File location | `~/.timmy/presence.json` — accessible to Workshop via bridge |
+| Staleness threshold | 5 minutes without liveness update = "not home" |
+| mood field | Optional. Workshop can render visual cues (color, animation) |
+
+## Consequences
+
+- **Timmy's agent loop** must write `~/.timmy/presence.json` as a side effect
+  of work. This is a hook at the end of each cycle, not a daemon.
+- **The Workshop frontend** reads this file and renders accordingly. Stale
+  liveness → dim the wizard, show "away" state.
+- **The WebSocket bridge** (#243) watches this file and pushes changes to
+  connected Workshop clients.
+- **Schema is versioned.** Breaking changes increment the version field.
+  Workshop must handle unknown versions gracefully (show raw data or "unknown state").
+
+## Related
+
+- #222 — Workshop epic
+- #243 — WebSocket bridge (transports this state)
+- #239 — Sensory loop (feeds into state)
+- #242 — 3D world (consumes this state for rendering)
+- #246 — Confidence as visible trait (mood field serves this)