feat: add explicit keyword routes for summer reading, find-a-library, sunday/opening hours

- 'summer reading'/'reading challenge' → summer-reading-challenge page
(was falling through to _keyword_search, no source, 3 messy chunks)
- 'find a library'/'library branches' etc → find-a-library page
(was falling through to _keyword_search, no source)
- 'sunday'/'opening hours'/'when do' → opening-hours page
(was returning only 91w from LU page; now 231w with Sunday-specific data)
All 32 topic navigator questions now grade A except 'book a computer'
which is correctly B — that page is genuinely sparse (walk-in, no booking).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

query_tool.py

@@ -577,6 +577,10 @@ class LibraryQueryTool:
             ("children", "storytime", "bounce and rhyme", "stay and play", "kids",
              "events", "activities", "activity", "sessions", "reading group",
              "coding club", "craft", "rhyme time"): "library-events-and-activities",
+            ("summer reading", "reading challenge", "summer holiday reading"): "summer-reading-challenge",
+            ("find a library", "nearest library", "library branches", "library locations",
+             "all libraries", "list of libraries", "where is the library"): "find-a-library",
+            ("sunday", "opening hours", "open on", "what time", "when do", "when does"): "opening-hours",
             ("disruption", "closed", "closure", "service disruption"): "library-service-disruption",
             ("computer", "pc", "book a computer", "internet access", "free computer"): "book-a-computer",
             ("printing", "photocopy", "photocopying", "scan", "scanner", "print"): "printing-and-photocopying-services",