feat(facets+ui): clickable facet values everywhere, genre prettify, active-filter chips

Frontend half of the faceted-navigation Phase 2. 'Everything filterable
should be clickable': every displayed facet value links to the bookshelf
pre-filtered by its raw stored value; display forms are prettified at
render, never in the DB.

- templates/facet_links.templ: FacetLink (inline links) + FacetBadge
  (badge links) to /bookshelf?<facet>_filter=<value>; the raw value
  rides the param while the shown text is prettified, so matching and
  display can never disagree. Series/tags keep their dedicated pages
  by design; the card media-type icon stays unlinked (a derived kind,
  not a column value — deep-linking it would send wrong values).
- book_detail.templ: publisher, language, edition, genre, imprint
  cells + narrators line + age-rating/story-arc badges are now links.
- prettifyGenre (templates/utils.go + unit tests): title-cases only
  entirely-lowercase values; small words stay down except first
  position; & preserved. TS port for chip labels documents the twin.
- bookshelf.templ + bookshelf.ts: active-filter chips bar — Alpine
  renders chips from client-local form state (sanctioned island);
  one bubbled htmx:afterRequest hook keeps chips + shareable URL in
  sync; removeFilterChip clears the facet and re-applies. URL deep
  links now accept all 18 facet params (hidden inputs where the
  drawer has no field).

Pins changelog: Batch B/C entry in docs/contract_pins.md. Rendering
ownership guard (make lint-rendering) green.

templates/bookshelf.templ

@@ -286,6 +286,28 @@ templ BookShelf(
 						</div>
 					</div>
 				</form>
+				<!-- Active-filter chips: a pure function of the client-side
+					form state (Alpine renders them, templ owns the look —
+					sanctioned TS island). Removing a chip clears that facet
+					and re-applies the form. -->
+				<div
+					id="active-filter-chips"
+					class="flex flex-wrap items-center gap-2 mb-4"
+					x-show="activeFilters.length > 0"
+					x-cloak
+				>
+					<template x-for="chip in activeFilters" :key="chip.param">
+						<button
+							type="button"
+							class="badge inline-flex items-center gap-1.5 hover:opacity-80 transition-opacity cursor-pointer"
+							style="background-color: var(--accent-muted); color: var(--accent); border: 1px solid transparent;"
+							@click="removeFilterChip(chip.param)"
+						>
+							<span x-text="chip.label"></span>
+							<span aria-hidden="true">×</span>
+						</button>
+					</template>
+				</div>
 				<div id="books-grid" class="grid grid-cols-2 md:grid-cols-4 lg:grid-cols-5 xl:grid-cols-6 gap-4">
 					@BooksGrid(books, limit, offset, count, currentLibraryID)
 					if errorMessage != "" {