docs(6210): acceptance sweep — src, scripts and frontend leftovers described in the present tense

The acceptance greps found what the per-area passes missed:

- src/scribe: "Phase 7/8" removal notes in projects, settings and
  user_profile; a paragraph promising an auto-summary side effect that no
  longer exists; user_profile's claim that "upcoming MCP profile tools" read
  the profile, which nothing does; an instance count and instance rule
  titles in plugin_context; "MILESTONE 323 DECIDED" in rulebooks.
- scripts/: check_plugin's header and inline comments were a history of
  the incidents behind each guard, with issue numbers in two failure
  messages; check_dangling_styles named this app's classes as its examples;
  check_design_tokens, measure_duplication and mint_plugin_version cited
  issues and checklists.
- frontend/src: forty-odd comments with four-digit issue numbers that the
  earlier frontend scan filtered out as hex colours, plus "used to" and
  "Phase N" notes.

Kept: illustrative ids (`#4181` as a bare-id example, `PR #198`), migration
Create Date headers and one migration's dated data floor, and the plugin
skills' worked examples of how to cite a record.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/scribe/services/plugin_context.py

@@ -1,16 +1,16 @@
 """Session-context rendering for the Scribe plugin's SessionStart hook.
 
 The plugin's hook curls `GET /api/plugin/context` at session start and injects
-the returned text as `additionalContext`, giving Scribe the same push channel
-that superpowers and file-memory have. This module renders that text.
+the returned text as `additionalContext`, giving Scribe a push channel into
+the session. This module renders that text.
 
 Design note — altitude: we inject rule *titles* grouped by topic (a compact
-index), NOT every rule's full statement. The 48 always-on statements run well
-past the 10k-char `additionalContext` cap, and the push channel's job is to make
+index), NOT every rule's full statement. A working rulebook's always-on statements run
+well past the 10k-char `additionalContext` cap, and the push channel's job is to make
 Claude *aware* the rules exist and *reach* for them — not to dump them. Full
 text stays one `get_rule(id)` / `search(content_type="rule")` call away. Titles are
-mostly self-describing ("`dev` is home", "No GitHub — Fabled-Git only"), so the
-index alone already steers behavior.
+mostly self-describing ("Run migrations before deploying"), so the index alone
+already steers behavior.
 """
 from __future__ import annotations