docs: remove dead references to a retired repository (green)

The annotation surface's provenance is now described as the pattern it
follows (pencil toggle, intent buttons, popover form, structured export)
rather than by naming a repository that no longer exists. Touches the
plugin/package descriptions, README, docs/architecture.md, the v5.0.3
CHANGELOG entry, and two comments in scripts/annotate.mjs and its test.

Retired-reference check: 12 hits in 7 files -> 0 (content and path names).

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

CHANGELOG.md

@@ -586,7 +586,7 @@ prose in each downstream command.
 - `phase_signals_present` stats emission is also deferred to v5.1.1
   (opt-in observability per Research 03 Q5).
 
-## v5.0.3 — 2026-05-13 — Annotation UX matches the claude-code-100x reference
+## v5.0.3 — 2026-05-13 — Annotation UX matches the operator's reference
 
 **No new breaking changes beyond v5.0.0.** Forks consuming v5.0.2's
 annotation HTML keep working — the file path and entry point are
@@ -597,8 +597,8 @@ freeform notes) with the v5.0.3 shape (intent-tagged annotations).
 ### Why
 
 v5.0.2 shipped a too-simple annotation surface: click a line, write a
-freeform note, save. The operator pointed at the existing
-`claude-code-100x/build-site.js` annotation system as the actual
+freeform note, save. The operator pointed at an existing
+annotation surface in another project as the actual
 reference — pencil-toggle mode, text-selection capture, three intent
 categories (**Fiks** / **Endre** / **Spørsmål**), a popover form at the
 cursor, structured markdown export with intent labels. v5.0.3 brings
@@ -613,7 +613,7 @@ don't repeat it.
 ### Changed
 
 - **`scripts/annotate.mjs`** — rewritten to match the
-  `claude-code-100x/build-site.js` UX:
+  reference annotation UX:
   - **Article rendering** — markdown is rendered to proper HTML elements
     (`<h1>`/`<p>`/`<ul>`/`<li>`/`<table>`/`<blockquote>`/`<pre>`), not as
     line-numbered raw lines. Document reads as a normal article.
@@ -659,8 +659,8 @@ don't repeat it.
 - `npm test`: 518 tests, 516 pass, 0 fail, 2 skipped (up from 516 — 2
   new annotate tests for hostile-content escape + renderMarkdown table/
   blockquote coverage).
-- Reference: `~/repos/claude-code-100x/claude-code-100x/build-site.js`
-  lines 1431–2255 (annotation UI section).
+- Reference: the annotation UI section of the existing surface the
+  operator pointed at.
 - Version bump 5.0.2 → 5.0.3 in `.claude-plugin/plugin.json`,
   `package.json`, `package-lock.json`, plugin `README.md` badge.