feat(mcp): enter_project becomes a small primer: goal, recent work, open work, vocabulary (#4045)

The handshake carried the whole project record, every milestone's plan, full
rule text, the notes most recently edited and ~9k of design guidance. For
project 2 that was ~222k characters, past what an MCP client accepts as a tool
result. Each category was walked through with the operator and sized to what a
session needs on arrival; each names the call that has the rest.

- project: id, title, status and the full goal (session start's "full goal"
  pointer still lands here). get_project keeps the whole record.
- milestone_summary: the 5 most recently touched milestones, any status, most
  recent first, without plans. Summaries gain last_touched_at: the later of
  the milestone's own edit and its newest step update, from the query that
  already counts steps. milestone_summary_omitted counts the rest and points
  to list_milestones. get_project and list_milestones list every milestone,
  also without plans.
- open_tasks: the 10 most recently touched open tasks, with or without a
  milestone, each naming its milestone. list_notes gains sort="touched"
  (the later of updated_at and the newest work-log), because a log doesn't
  bump updated_at.
- recent_notes: dropped. Retrieval surfaces notes by relevance, and
  get_recent covers recency.
- systems: id and name.
- design_system: summary plus guidance_call. get_design_system gains
  resolved_guidance, the chain-merged prose; its own guidance field is only
  the departures, so session start's old pointer to it led to a fragment.
  The session start pointer and using-scribe's "Building UI" section now
  name resolved_guidance.
- rules: rules_payload(brief=True) gives project_rules as id and title plus
  subscribed_rulebooks, and records only what it shows. Retrieval delivers
  rules in full and ignores subscriptions (#4052). Other callers unchanged.
- pattern_coverage, inception and systems_bootstrap: unchanged.

Clients: the plugin's using-scribe skill, the compaction notice and session
start are updated here; the REST project summary only gains last_touched_at.
Plugin version minted.

Tests: a size ceiling on the handshake for a large project; milestone and
task selection and naming; brief rules; resolved_guidance; the session
start pointer; and a real-Postgres test that a work-log touches its task and
a step update touches its milestone.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01821k5B3Ysecp9fNYs92Kuy

src/scribe/services/rulebooks.py

@@ -1306,7 +1306,9 @@ async def get_applicable_rules(
     }
 
 
-def rules_payload(applicable: dict, *, user_id: int | None, source: str) -> dict:
+def rules_payload(
+    applicable: dict, *, user_id: int | None, source: str, brief: bool = False,
+) -> dict:
     """The caller-facing shape of a get_applicable_rules() result.
 
     Every surface that hands rules to an agent (enter_project, get_project,
@@ -1333,7 +1335,25 @@ def rules_payload(applicable: dict, *, user_id: int | None, source: str) -> dict
     (`plugin_context`) — computed a marker and showed nobody
     anything, and counting those would put rules in the denominator that no
     agent ever saw.
+
+    `brief` is the session handshake's form (#4045): the project's own rules
+    as id and title, and the subscribed rulebooks, nothing else. Rules reach a
+    session in full by retrieval, which ignores subscriptions, so the handshake
+    lists which constraints exist rather than restating them; get_rule reads
+    one. Only what is shown is recorded as surfaced.
     """
+    if brief:
+        project_rules = [
+            {"id": r["id"], "title": r["title"]}
+            for r in applicable.get("project_rules", [])
+        ]
+        record_rule_surfaced(
+            user_id=user_id, rule_ids=[r["id"] for r in project_rules], source=source,
+        )
+        return {
+            "project_rules": project_rules,
+            "subscribed_rulebooks": applicable["subscribed_rulebooks"],
+        }
     record_rule_surfaced(
         user_id=user_id,
         rule_ids=(