refactor(mcp): one rules_payload() for every surface that hands rules to an agent; drop the dead bearer resolver (#2828, milestone 296 area 4)

Reading the 16 tool modules against each other: the six-key applicable-rules
block (applicable_rules, applicable_rules_truncated, subscribed_rulebooks,
project_rules, suppressed_rules, suppressed_topics) was hand-built in five
places — enter_project, get_project, get_task (legacy plans), get_milestone
(three of the six) and services/planning.start_planning. rulebooks_svc.
rules_payload() is now the one place that names them; get_milestone gains the
three it lacked, so every rules-carrying payload reads the same. list_rules /
list_always_on_rules share _rule_summary. mcp/auth.resolve_bearer_to_user_id
duplicated resolve_bearer's parsing and had no product caller (only its own
tests) — removed; the tests now exercise resolve_bearer.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/scribe/mcp/tools/rulebooks.py

@@ -193,6 +193,12 @@ async def delete_topic(topic_id: int, confirmed: bool = False) -> dict:
 
 # ── Rule CRUD ──────────────────────────────────────────────────────────
 
+def _rule_summary(r) -> dict:
+    """The list-row shape for a rule: what an agent needs to APPLY it. The
+    full record (why, how_to_apply, timestamps) is get_rule's job."""
+    return {"id": r.id, "title": r.title, "statement": r.statement, "topic_id": r.topic_id}
+
+
 async def list_rules(
     rulebook_id: int = 0, topic_id: int = 0, project_id: int = 0,
 ) -> dict:
@@ -213,16 +219,7 @@ async def list_rules(
         topic_id=topic_id or None,
         project_id=project_id or None,
     )
-    return {
-        "rules": [
-            {
-                "id": r.id, "title": r.title, "statement": r.statement,
-                "topic_id": r.topic_id,
-            }
-            for r in rows
-        ],
-        "total": len(rows),
-    }
+    return {"rules": [_rule_summary(r) for r in rows], "total": len(rows)}
 
 
 async def list_always_on_rules() -> dict:
@@ -235,16 +232,7 @@ async def list_always_on_rules() -> dict:
     """
     uid = current_user_id()
     rules = await rulebooks_svc.list_always_on_rules(uid)
-    return {
-        "rules": [
-            {
-                "id": r.id, "title": r.title, "statement": r.statement,
-                "topic_id": r.topic_id,
-            }
-            for r in rules
-        ],
-        "total": len(rules),
-    }
+    return {"rules": [_rule_summary(r) for r in rules], "total": len(rules)}
 
 
 async def get_rule(rule_id: int) -> dict: