docs(memory): add W8 — first-class extension point entity (EP-CUST-001)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

memory/working/260224-wishlist-custodian.md

@@ -187,6 +187,30 @@ whether the API is up, so the agent knows before trying to use the tools.
 
 ---
 
+### W8 — First-class extension point entity in state hub schema (EP-CUST-001)
+
+**Problem:** Extension points are currently recorded as `progress_events` with
+`event_type=extension_point` and structured `detail` JSON. This works for now
+but lacks dedicated querying, filtering, dashboard views, and cross-project
+aggregation.
+
+**Convention (current):** `EP-{PROJECT}-{NNN}` IDs, inline markers in spec docs,
+`## Extension Points` summary section at doc end, recorded via `add_progress_event`
+with `event_type=extension_point`.
+
+**Fix:** When the number of tracked EPs across projects grows enough to warrant it,
+add a first-class `extension_points` table to the state-hub schema with fields:
+`ep_id`, `topic_id`, `workstream_id`, `location`, `trigger`, `constraint`,
+`current_approach`, `status` (open/resolved/superseded).
+
+**Constraint:** Must be backward-compatible — existing `progress_event` records
+with `event_type=extension_point` should remain queryable or be migrated.
+
+**Trigger:** When cross-project EP aggregation is needed in the dashboard, or when
+EPs need to be surfaced in `get_state_summary()`.
+
+---
+
 ## Priority Order
 
 | # | Item | Effort | Token Saving | Do When |
@@ -198,3 +222,4 @@ whether the API is up, so the agent knows before trying to use the tools.
 | W5 | `TOOLS.md` reference card | 30 min | 2,500 / session | Next custodian session |
 | W4 | Topic IDs in canon charters | 20 min | 200 / registration | Low urgency |
 | W7 | SessionStart hook for API health | 30 min | Indirect | After W2 |
+| W8 | First-class EP entity in state hub (EP-CUST-001) | 2–4 hr | Indirect | When EP count warrants it |