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>

scripts/mint_plugin_version.py

@@ -11,7 +11,7 @@ Installs fetch it straight from this git repo via `.claude-plugin/
 marketplace.json`, so **a push IS the release** — there is no build between
 you committing and a user fetching, and therefore no moment at which CI could
 stamp a version in. Every other artifact in the family derives its version
-during a build (note #3127 §2). This one has no build to derive during.
+during a build. This one has no build to derive during.
 
 WHICH CLOCK, AND WHY IT DIFFERS FROM THE SERVER IMAGE — the divergence is
 deliberate, and it lives one directory away from its opposite, so it is
@@ -27,8 +27,7 @@ one lane and no build, so that reason does not reach it and paying its cost
 buys nothing. What is given up is reproducibility-from-history: you cannot
 recompute this value later, only verify that it moved when it had to.
 
-That trade is acceptable ONLY because of what #3325 established by reading the
-installer's code: the refresh test is `P.version === H`, plain string
+That trade is acceptable ONLY because of what the installer's code does: the refresh test is `P.version === H`, plain string
 equality, with no ordering comparison anywhere. Where a comparator ORDERS, an
 unreproducible version is dangerous — nothing can check it is right. Where it
 only tests equality, "did it change when it should have" is the entire
@@ -52,8 +51,8 @@ ROOT = Path(__file__).resolve().parents[1]
 MANIFEST = ROOT / "plugin" / ".claude-plugin" / "plugin.json"
 
 # Four dot-separated numeric fields, zero-padded, and nothing else — one shape
-# for every human-readable version in the family (#3127 checklist 10). The
-# padding is load-bearing for the midnight case the checklist names by hand:
+# for every human-readable version in the family. The padding is
+# load-bearing for the midnight case:
 # 2026.01.05.0000, which an unpadded `%-H%M` would render as `0` and silently
 # shorten. Harmless while nothing orders these, wrong the moment anything does.
 VERSION_RE = re.compile(r"^\d{4}\.\d{2}\.\d{2}\.\d{4}$")