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).

docs/SPEC-PIN.md

@@ -7,11 +7,18 @@ documents the pin, the vendored artifacts, and the bump procedure.
 
 | Field | Value |
 |---|---|
-| Worldtree git SHA | `55101e909abcd2219833266b6f905c5bc956e0f0` |
-| Worldtree HEAD message | `memory: snapshot — #177 Vili v1 + persona async-decouple shipped as v0.19.0` |
-| Pinned on | 2026-05-20 |
-| Pinned by | brokkr-smithy-dev (initial scaffold) |
-| Worldtree version at pin | `v0.19.0` |
+| Worldtree git SHA | `da93ca7cf613f1dc229a7a44d07fc1d7efc78e25` |
+| Worldtree HEAD message | `feat(#204): v0.28.0 — persona-state observability surface` |
+| Pinned on | 2026-05-25 |
+| Pinned by | ratatoskr-dev (bump for #204 affect_update SSE) |
+| Worldtree version at pin | `v0.28.0` |
+
+## Pin history
+
+| Date | SHA | Version | Notable deltas consumed |
+|---|---|---|---|
+| 2026-05-25 | `da93ca7` | v0.28.0 | #204 — new SSE event `affect_update` (current/scheduled), new endpoint `GET /agents/{id}/persona_state` (not yet consumed), auth-model doc edits |
+| 2026-05-20 | `55101e9` | v0.19.0 | initial scaffold pin |
 
 ## Vendored artifacts