feat(sse,tui): bump spec pin to v0.28.0 + AffectUpdate event (v0.11.0)

Spec pin moved 55101e9 (v0.19.0) → da93ca7 (v0.28.0); vendored
conversation-api-spec.md + conversation_api.contract.md re-snapshotted
from Worldtree at the new SHA. The only material delta consumed in
this bump is Worldtree #204's affect_update SSE event surface.

Wire layer (sse_client.py):
- New AffectUpdate dataclass: sse_id / status / turn_id / snapshot
  (snapshot is None for status="scheduled")
- Added to Event union + _envelope_for_type dispatch branch
- Without this, ratatoskr would crash on any persona-enabled turn
  from a v0.28.0 server (unknown SSE event type → ValueError)

TUI layer (tui.py):
- AffectUpdate routes through the v0.10.0 audit pipeline only — one
  debug-pane line per arrival with dominant_emotion + PAD for
  status="current", lightweight status+turn_id for status="scheduled"
- No transcript / tools / thinking pane writes — the persona UX shape
  (Persona TabPane vs sticky header line) is deferred to a separate
  bump pending operator direction

Tests: 2 new wire-layer tests for current+scheduled parsing + 2 new
presenter audit tests for routing and audit-line shape.

Not yet consumed: GET /agents/{id}/persona_state endpoint (step 2 of
the integration plan).

tests/test_sse_client.py

@@ -5,6 +5,7 @@ import pytest
 import respx
 
 from ratatoskr.sse_client import (
+    AffectUpdate,
     CancelAlreadyCompleted,
     Cancelled,
     CancelResult,
@@ -877,3 +878,80 @@ class TestEmptyDataSkipped:
         assert exc_info.value.raw == "x" * 200
         # Exception message also only contains the truncated form
         assert "x" * 5000 not in str(exc_info.value)
+
+
+class TestAffectUpdate:
+    """Worldtree #204 / v0.28.0 — persona-state observability SSE event.
+
+    Two emissions per qualifying turn (persona-enabled agent, non-ephemeral
+    session): `status: "current"` at turn start with full snapshot, then
+    `status: "scheduled"` near turn end (lightweight, no snapshot).
+
+    See docs/conversation-api-spec.md § affect_update.
+    """
+
+    @respx.mock
+    async def test_current_status_parsed_with_snapshot(self) -> None:
+        """current_status_parsed_with_snapshot [tracer]: status=current carries
+        the full snapshot dict; AffectUpdate.snapshot is populated with the
+        nested PAD / dominant_emotion / emotions_active fields.
+        """
+        snapshot = {
+            "agent_id": "mimir",
+            "pad": {"pleasure": 0.52, "arousal": 0.47, "dominance": 0.50},
+            "dominant_emotion": "curiosity",
+            "emotions_active": [
+                {"type": "curiosity", "intensity": 0.6, "decay_remaining_s": 202.7}
+            ],
+            "baseline_pad": {"pleasure": 0.50, "arousal": 0.40, "dominance": 0.50},
+            "mood_drift": {"valence_delta": 0.02, "arousal_delta": 0.07},
+            "last_updated_at": "2026-05-25T22:30:18+00:00",
+        }
+        stream = _sse_chunk(
+            "42:1",
+            {
+                "type": "affect_update",
+                "status": "current",
+                "turn_id": 42,
+                "snapshot": snapshot,
+            },
+        ) + _sse_chunk("42:2", _DONE_42_6)
+        respx.post("https://w.example/sessions/s1/messages").mock(
+            return_value=httpx.Response(
+                200, headers={"content-type": "text/event-stream"}, content=stream
+            )
+        )
+        async with httpx.AsyncClient(base_url="https://w.example") as client:
+            events = [e async for e in stream_turn(client, "s1", "hi")]
+        affect = events[0]
+        assert isinstance(affect, AffectUpdate)
+        assert affect.status == "current"
+        assert affect.turn_id == 42
+        assert affect.snapshot == snapshot
+        assert affect.sse_id == SseId(42, 1)
+
+    @respx.mock
+    async def test_scheduled_status_parsed_no_snapshot(self) -> None:
+        """scheduled_status_parsed_no_snapshot [trace]: status=scheduled carries
+        no snapshot field; AffectUpdate.snapshot is None.
+        """
+        stream = (
+            _sse_chunk("42:1", {"type": "text", "content": "x"})
+            + _sse_chunk(
+                "42:2",
+                {"type": "affect_update", "status": "scheduled", "turn_id": 42},
+            )
+            + _sse_chunk("42:3", _DONE_42_6)
+        )
+        respx.post("https://w.example/sessions/s1/messages").mock(
+            return_value=httpx.Response(
+                200, headers={"content-type": "text/event-stream"}, content=stream
+            )
+        )
+        async with httpx.AsyncClient(base_url="https://w.example") as client:
+            events = [e async for e in stream_turn(client, "s1", "hi")]
+        affect = next(e for e in events if isinstance(e, AffectUpdate))
+        assert affect.status == "scheduled"
+        assert affect.turn_id == 42
+        assert affect.snapshot is None
+        assert affect.sse_id == SseId(42, 2)