fix(gen): resolver registry describes the template language again

Seven registered {{PLACEHOLDER}}s had zero uses in any .tmpl (checked in both
bare and :arg forms): REDACT_TAXONOMY_TABLE, TEST_COVERAGE_AUDIT_REVIEW,
MODEL_OVERLAY, QUESTION_PREFERENCE_CHECK, QUESTION_LOG, INLINE_TUNE_FEEDBACK,
MAKE_PDF_SETUP. The last two of those families are invoked programmatically by
preamble.ts (functions kept, registry entries dropped); the question-tuning
trio and the review coverage-audit wrapper were documented by their own module
as existing 'for unit testing' that no test performed — deleted, along with
generateRedactTaxonomyTable + its EXAMPLE/TIER_BLURB constants (its '/cso
renders the full table' comment was itself stale) and its test describe.

Also deletes the gated-resolver mechanism (ResolverEntry/appliesTo/
unwrapResolver + test/resolver-entry.test.ts): fully built, fully tested,
used by zero of the 65 registry entries — the generator loop simplifies to a
direct function call. CLAUDE.md's redact-doc line stops advertising the dead
token.

Proof: zero-diff regen (0 SKILL.md changed); gen-skill-docs + skill-validation
737 tests green.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

CLAUDE.md

@@ -494,7 +494,7 @@ determined leaker (a CHANGELOG line that does would fail a hostile screenshotter
   `--auto-redact`, `--repo-visibility`, `--from-file`). `bin/gstack-redact-prepush`
   is the opt-in git hook.
 - **Skill docs are generated** from `scripts/resolvers/redact-doc.ts`
-  (`{{REDACT_TAXONOMY_TABLE}}`, `{{REDACT_INVOCATION_BLOCK:<sink>}}`) so /spec,
+  (`{{REDACT_INVOCATION_BLOCK:<sink>}}`) so /spec,
   /cso, /ship, /document-release, /document-generate never drift from the engine.
 - **Scan-at-sink:** always scan the EXACT bytes that will be sent — write to a
   temp file, scan that file, pass the SAME file to `gh`/`git`. Never scan a string