cleanup: dead-code inventory — 12 unreferenced symbols, 18 unnecessary exports, 1 orphan script

[JonasJesus42]

Audit of what bun run deadcode (knip) reports, classified — the raw output mixes three very
different things and only one of them is actually dead.

Measured by counting references to each symbol in the file that defines it: one occurrence means it
is defined and never called anywhere; more than one means it is used in-module and the export is
what is unnecessary.

1. Defined and never called — 12 symbols

symbol	file	note
buildFastStoreNextTheme	migrate/targets/faststore-next.ts	behaviour gap — filed separately as #309
ALL_REPORT_SECTIONS	report/extract-section.ts	looks like it was meant to validate --section. Today an invalid name reaches the extractor and comes back as section "naoexiste" not present in this report — which reads like the section is missing from this run rather than not existing at all
promptForSelector	engine/interactive-selector-prompt.ts	a whole interactive prompt, never wired. Feature that was built and never connected, or superseded by LLM selector discovery?
providerName, getLlmLanguage	llm/client.ts	providerLabel is the one that gets used
LLM_MODEL_ANTHROPIC, LLM_MODEL_OPENROUTER	llm/client.ts	superseded by llm/models.ts
isComponentRefineLlmAvailable	llm/component-refine.ts	sibling isComponentDetectionLlmAvailable is used
PLP_STEP_LABELS, SPA_NAVIGATION_CRITICAL_STEPS	checks/lib/step-names.ts
pageRoleHint	checks/lib/pairing.ts
__TEST__	llm/resolve-search-terms.ts	test hook nothing imports

2. Used in-module, export unnecessary — 18 symbols

fetchLlmsTxtQuality, classifyAll, fetchDecoPages, USER_AGENT_BY_VIEWPORT,
extractAgentA11y, SEVERITY_WEIGHTS, DECAY_K, effectiveRate, SelectorCacheEntrySchema,
ALL_FEATURES, PREMIUM_FEATURE_TIER, nodeFetchText, findPage, SOURCES, SOURCE_BY_KIND,
TARGETS, buildWaterfallRows, formatMs.

Not dead — dropping the keyword is a one-line change each. Caveat worth deciding before touching
these: @decocms/parity is a published package, so an export may be someone's public API even
with no in-repo consumer. Since dist/cli.js is a bundle and the package has no library entry
point in exports, I believe none of these are reachable by a consumer — but that is worth
confirming rather than assuming.

findPage is mine, from #294. Happy to unexport it.

3. Also flagged

• scripts/regen-report.ts — reported as an unused file. It is a maintainer utility run by
  hand (bun run scripts/regen-report.ts), which knip cannot see. Either add it to knip's entry
  patterns or drop it if parity report --deck/serve covered its purpose.
• @types/diff — unused devDependency. diff ships its own types now.
• 34 unused exported types — same in-module-vs-public question as section 2, lower stakes.

Suggested split

• migrate: buildFastStoreNextTheme is never called — --target faststore-next silently skips theme generation #309 for the theme gap (behaviour, separate)
• one PR for section 1, deleting after a quick check that each is really superseded — ALL_REPORT_SECTIONS and promptForSelector deserve a decision rather than a delete
• one mechanical PR for section 2 + 3 once the published-API question is settled

Not doing any of it blind: deleting something that turns out to be a half-finished feature is worse
than leaving it, which is why the list is split by why it is unreferenced instead of just being a
list.