search: make the navigation form work from every page (AUD-151)

The nav form carried hx-get="/search" hx-target="#search-results", but
#search-results exists only on /search. On every other page htmx found no
target and silently discarded the response: a search box that looks like it
works and does nothing.

- SearchForm is now a plain GET with no htmx attributes (navigation and the
  landing page), so it navigates to /search?q=… from any page and with
  JavaScript disabled.
- SearchFormLive keeps the in-place swap on the search page, where the target
  does exist. For HX-Request the server now returns the block's *contents*
  (SearchResultsBody), so the fragment no longer nests a second element with
  id="search-results" inside the live region.
- Empty query shows a prompt instead of an empty list. A zero-match query says
  "Nothing found" and offers the six areas plus the evidence index.
- The result count is role="status" inside the existing aria-live container, so
  a screen reader reads "4 results for …" rather than a run of titles.

Tests (internal/server, internal/site):
- the nav form carries no htmx attribute on nine pages, and no built page
  carries an hx-target whose element is missing (walks all of dist/);
- search submitted from /, /edge/ and /platform/ lands on a page with results
  with no HX-Request header, i.e. the JavaScript-disabled path;
- empty query, zero match and the announced count;
- a content change followed by a build is visible in dist/search.db. That is
  the deploy path: deploy/deploy.sh runs `make dist` before it stages a
  release, and search.Build removes and rewrites the index every build.

DoD: search from home, /edge and /platform lands on results; works with
JavaScript disabled; zero-match query shows a message; content change followed
by a deploy is reflected in search; no htmx request targets a missing element.

(cherry picked from commit a56c795768e1e9b10204aae04c3612d7a96775a7)

internal/web/templates/pages.templ

@@ -135,40 +135,67 @@ templ SearchPage(v SearchView) {
 				<h1>Search { strconv.Itoa(v.Indexed) } pages</h1>
 				<p class="doc-claim">Full-text search over page titles and body text. Served from a local index — no model, no network call.</p>
 			</header>
-			@SearchForm(v.Query, "page-search")
+			@SearchFormLive(v.Query, "page-search")
 			@SearchResults(v)
 		</article>
 	}
 }
 
-// SearchResults is swapped into #search-results by HTMX.
+// SearchResults is the results block as a page element: the live region wrapper
+// plus its contents, which is what the whole page renders. Without JavaScript the
+// form reloads the page and this markup arrives in the document.
 templ SearchResults(v SearchView) {
 	<div id="search-results" aria-live="polite">
-		if v.Query == "" {
-			<p class="section-note">Try “zigbee”, “signage”, “routing”, “backups” or “guardrails”.</p>
-		} else if v.Failed {
-			<p class="search-empty">That query could not be run. Try fewer or simpler words.</p>
-		} else if len(v.Results) == 0 {
-			<p class="search-empty">No page matches <q>{ v.Query }</q>. The <a href="/evidence/">evidence index</a> lists everything by area.</p>
-		} else {
-			<p class="search-count">{ strconv.Itoa(len(v.Results)) } results for <q>{ v.Query }</q></p>
-			<ol class="results">
-				for _, r := range v.Results {
-					<li class="result">
-						<h2><a href={ templ.SafeURL(r.URL) }>{ r.Title }</a></h2>
-						<p class="result-meta">
-							<span class="kind">{ r.Area }</span>
-							<span class="kind">L{ strconv.Itoa(r.Level) }</span>
-							<span class={ ConfidenceClass(r.Confidence) }>{ r.Confidence }</span>
-						</p>
-						<p class="result-snippet">@SafeSnippet(r.Snippet)</p>
-					</li>
-				}
-			</ol>
-		}
+		@SearchResultsBody(v)
 	</div>
 }
 
+// SearchResultsBody is the results block without the live region. This is what an
+// htmx request returns: the search page's form swaps it into #search-results with
+// innerHTML, so returning the wrapper too would nest a second element with the
+// same id inside the first and make the live region announce twice.
+//
+// Everything here arrives inside the polite live region, and the count carries
+// role="status" on top of that, so the number is read as one utterance instead of
+// a run of result titles.
+templ SearchResultsBody(v SearchView) {
+	if v.Query == "" {
+		<p class="search-empty">Type one or two words above and press Enter. Good starting points: “zigbee”, “signage”, “routing”, “backups”, “guardrails”.</p>
+	} else if v.Failed {
+		<p class="search-empty">That query could not be run. Try fewer or simpler words.</p>
+	} else if len(v.Results) == 0 {
+		<p class="search-empty">Nothing found for <q>{ v.Query }</q>. Try a shorter or more general word, or browse an area:</p>
+		@searchAreaLinks(v.Areas)
+	} else {
+		<p class="search-count" role="status">{ strconv.Itoa(len(v.Results)) } results for <q>{ v.Query }</q></p>
+		<ol class="results">
+			for _, r := range v.Results {
+				<li class="result">
+					<h2><a href={ templ.SafeURL(r.URL) }>{ r.Title }</a></h2>
+					<p class="result-meta">
+						<span class="kind">{ r.Area }</span>
+						<span class="kind">L{ strconv.Itoa(r.Level) }</span>
+						<span class={ ConfidenceClass(r.Confidence) }>{ r.Confidence }</span>
+					</p>
+					<p class="result-snippet">@SafeSnippet(r.Snippet)
+</p>
+				</li>
+			}
+		</ol>
+	}
+}
+
+// searchAreaLinks is the way out of an empty result: the six areas plus the
+// evidence index, so a failed search never leaves the reader at a dead end.
+templ searchAreaLinks(areas []LinkView) {
+	<ul class="search-areas">
+		for _, a := range areas {
+			<li><a href={ templ.SafeURL(a.Href) }>{ a.Label }</a></li>
+		}
+		<li><a href="/evidence/">Evidence index</a></li>
+	</ul>
+}
+
 // StreamPage proves the panel can be re-pointed at a stream. The layout and the
 // panel markup are the ones every other page uses; only the binding differs.
 templ StreamPage(v StreamView) {