Fix file numbering: WAW is 06, Dublin is 07

Renumber all WAW files 07*→06* and Dublin 06→07 to reflect
actual route order (WAW comes before Dublin). Fix all
cross-references in README, .ai-context.md, Belfast, and
WAW overview.

.ai-context.md

@@ -54,8 +54,8 @@ Official WAW direction is north→south. Cycling this way means headwinds on exp
     ├── 03-iom-ferry.md              # (to be created)
     ├── 04-isle-of-man.md
     ├── 05-belfast.md
-    ├── 06-dublin.md
-    ├── 07-wild-atlantic-way.md
+    ├── 06-wild-atlantic-way.md  # + 06a–06g section files
+    ├── 07-dublin.md
     └── 08-return-via-france.md
 ```
 
@@ -93,7 +93,7 @@ Brief pitch.
 2. Keep numbering sequential to preserve route order
 3. Opinionated recommendations over exhaustive lists
 4. When referencing ferry bookings, always note if booking in advance is essential
-5. Wild Atlantic Way detail lives in `07-wild-atlantic-way.md` — for individual WAW stops, add subsections there rather than new files
+5. Wild Atlantic Way detail lives in `06-wild-atlantic-way.md` — for individual WAW stops, add subsections there rather than new files
 6. Update the README navigation table when adding new files
-7. Dublin (file 06) is the confirmed end-anchor — events on Aug 30/31 are fixed constraints
+7. Dublin (file 07) is the confirmed end-anchor — events on Aug 30/31 are fixed constraints
 8. The return leg (file 08) targets Sep 2 arrival in Walldorf — don't suggest itinerary extensions past Sep 1