feat: opt-in Journal search page and JournalSearchBox

- journal.routes.search (off by default) registers journal-search, the
  results page for ?q= in the API's relevance order (no sort is sent),
  server-rendered with a Polish-aware result count.
- JournalSearchBox: an icon button and a WAI-ARIA combobox with debounced
  ?fields=suggest suggestions, stale answers dropped, query words marked
  ignoring diacritics; a plain GET form without JS.
- The module keeps the search path out of the route cache and the sitemap
  and marks it noindex, follow.
- Client: suggestPosts and the fields option; useJournalLinks.searchLink.

app/utils/client.ts

@@ -9,6 +9,7 @@ import type {
   JournalPage,
   JournalPost,
   JournalPostDetail,
+  JournalPostSuggestion,
   JournalTag,
 } from './types.ts'
 
@@ -18,8 +19,18 @@ export const JOURNAL_MAX_PER_PAGE = 30
 /** The Journal API's per_page default. */
 export const JOURNAL_DEFAULT_PER_PAGE = 9
 
-/** Issues one GET for `path` (e.g. "/posts") with `query`, resolving the parsed JSON. */
-export type JournalFetcher = (path: string, query?: Record<string, string | number>) => Promise<unknown>
+/** Search terms shorter than this are ignored by the API, so the layer never sends them. */
+export const JOURNAL_SEARCH_MIN_LENGTH = 3
+
+/**
+ * Issues one GET for `path` (e.g. "/posts") with `query`, resolving the parsed
+ * JSON. `init.signal` aborts the request.
+ */
+export type JournalFetcher = (
+  path: string,
+  query?: Record<string, string | number>,
+  init?: { signal?: AbortSignal },
+) => Promise<unknown>
 
 export interface PostListOptions {
   page?: number
@@ -30,6 +41,13 @@ export interface PostListOptions {
   category?: string
   tag?: string
   search?: string
+  /** "suggest" asks for JournalPostSuggestion rows instead of full posts. */
+  fields?: 'suggest'
+}
+
+export interface SuggestOptions {
+  perPage?: number
+  signal?: AbortSignal
 }
 
 export interface AuthorPostListOptions {
@@ -56,6 +74,7 @@ export function buildPostListQuery(opts: PostListOptions = {}): Record<string, s
   if (opts.category) q.category = opts.category
   if (opts.tag) q.tag = opts.tag
   if (opts.search) q.search = opts.search
+  if (opts.fields) q.fields = opts.fields
   return q
 }
 
@@ -90,6 +109,11 @@ export function isNotFound(err: unknown): boolean {
 export interface JournalClient {
   getPost(slug: string): Promise<JournalPostDetail | null>
   listPosts(opts?: PostListOptions): Promise<JournalPage<JournalPost>>
+  /**
+   * Suggestion rows for `term` in relevance order (no sort is sent). A term
+   * shorter than JOURNAL_SEARCH_MIN_LENGTH sends nothing and gives an empty page.
+   */
+  suggestPosts(term: string, opts?: SuggestOptions): Promise<JournalPage<JournalPostSuggestion>>
   listCategories(): Promise<JournalCategory[]>
   findCategory(slug: string): Promise<JournalCategory | null>
   listTags(): Promise<JournalTag[]>
@@ -123,6 +147,17 @@ export function createJournalClient(fetcher: JournalFetcher): JournalClient {
       return (await fetcher('/posts', buildPostListQuery(opts))) as JournalPage<JournalPost>
     },
 
+    async suggestPosts(term, opts = {}) {
+      const search = term.trim()
+      const perPage = clampPerPage(opts.perPage ?? 5)
+      if ([...search].length < JOURNAL_SEARCH_MIN_LENGTH) {
+        return { data: [], meta: { current_page: 1, last_page: 1, per_page: perPage, total: 0 } }
+      }
+      const query = buildPostListQuery({ search, fields: 'suggest', perPage })
+      const init = opts.signal ? { signal: opts.signal } : undefined
+      return (await fetcher('/posts', query, init)) as JournalPage<JournalPostSuggestion>
+    },
+
     listCategories,
 
     async findCategory(slug) {