feat(plugin): make using-scribe skill actively pull standing rules

The SessionStart push channel cannot reliably deliver a sensitive API
token to the hook subprocess (upstream Claude Code bug anthropics/
claude-code#62442 — sensitive plugin userConfig is not persisted and is
absent on a normal session). Stop depending on that push for standing
rules: make the using-scribe bootstrap skill own the load instead.

- description: name the FIRST ACTION (list_always_on_rules + enter_project
  when a repo/project is in scope) so it auto-surfaces at session start
- add a 'Do this first' block instructing an active pull; demote the
  SessionStart hook to a bonus, not a precondition (it fail-opens and may
  be absent)
- reflex step 2: rules come from list_always_on_rules(), not from an
  assumed SessionStart injection

The hook + hooks.json are left in place: they fail-open and resume adding
value automatically if #62442 is fixed or the token is made non-sensitive.

Refs #755 (Phase 1: push channel descoped to optional; pull is load-bearing)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

plugin/skills/using-scribe/SKILL.md

@@ -1,6 +1,6 @@
 ---
 name: using-scribe
-description: Use at the start of any session and before answering questions about the operator's work or starting a task — establishes the Scribe-first reflex (recall before acting, load standing rules, update over duplicate, plan in Scribe not in files).
+description: Use at the START of every session, and before answering anything about the operator's work or starting any task — establishes the Scribe-first reflex. FIRST ACTION of a session: call list_always_on_rules() (and enter_project when a repo/project is in scope) to load the operator's binding rules. Then recall before acting, update over duplicate, plan in Scribe not in files.
 ---
 
 # Using Scribe
@@ -10,6 +10,20 @@ milestones, events, typed entities) and rulebook, reachable through the bundled
 `scribe` MCP server. Its value is mostly in what it **already holds** — so make
 reading it a reflex, not something you wait to be asked for.
 
+## Do this first (every session)
+
+**Pull the standing rules yourself — do not wait for them to be handed to you.**
+At the start of a session, before substantive work, call
+`list_always_on_rules()` to load the operator's always-on rules. If the working
+repo maps to a Scribe project (you're in a known repo, or `list_repo_bindings`
+shows a binding), call `enter_project(id)` instead/as-well — it returns the
+project plus its applicable rules, open tasks, and recent notes in one shot.
+
+Do this actively. A SessionStart hook *may* also inject a rule index, but treat
+that as a bonus, not a precondition: it can be absent (e.g. when the instance is
+unreachable, or the token didn't reach the hook), so the reliable path is this
+explicit pull. Rules loaded this way are **binding** for the session.
+
 ## The reflex
 
 1. **Recall before acting.** Before answering a question about the operator's
@@ -18,11 +32,10 @@ reading it a reflex, not something you wait to be asked for.
    re-deriving it or opening a duplicate. When a project is in scope, pass its
    `project_id` so results stay scoped.
 
-2. **Standing rules are binding.** The SessionStart context lists the operator's
-   always-on rule titles. Treat them as binding. Pull full text with
-   `list_always_on_rules()` or `get_rule(id)` when a rule is about to bite.
-   When a project is in scope, `enter_project(id)` also returns its applicable
-   rules.
+2. **Standing rules are binding.** Load them via `list_always_on_rules()` at
+   session start (see "Do this first"); treat every one as binding. Pull a
+   rule's full statement with `get_rule(id)` when it's about to bite. When a
+   project is in scope, `enter_project(id)` also returns its applicable rules.
 
 3. **Update over duplicate.** When recording, prefer updating an existing
    note/rule/task over creating a new one. Search first; revise what's there.