refactor(router): make v2RouteName the single authority for the v2 name rule

Moves the `v2-` de-dup (needed because getPascalCaseRouteName folds the
v2/ URL segment into the base) into the unit-tested v2RouteName helper
and simplifies the vite.config.ts call site to v2RouteName(raw, nodePath).
Removes the duplicated isV2 detection. No behavioural change: /v2/dashboard
still resolves to route name v2-dashboard; v1 names unchanged. Addresses
the Task 3 code-review Important finding.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

apps/app/vite.config.ts

@@ -38,26 +38,16 @@ export default defineConfig({
 
         // Defensive path read: unplugin-vue-router 0.8.8 TreeNode exposes
         // `.fullPath`; fall back to `.value.path` then '' so a future
-        // plugin bump can't silently drop the v2- prefix. Step 5 below
-        // empirically verifies the emitted name.
+        // plugin bump can't silently drop the v2- prefix.
         const nodePath
           = (routeNode.fullPath
             ?? routeNode.value?.path
             ?? '') as string
 
-        // getPascalCaseRouteName includes the 'v2' segment from the URL
-        // path prefix set by routesFolder (e.g. 'v2/dashboard' → 'v2-dashboard').
-        // Strip that prefix before v2RouteName re-adds the canonical `v2-`
-        // so we get 'v2-dashboard' not 'v2-v2-dashboard'.
-        const isV2
-          = nodePath === '/v2'
-          || nodePath === 'v2'
-          || nodePath.startsWith('/v2/')
-          || nodePath.startsWith('v2/')
-
-        const base = isV2 && raw.startsWith('v2-') ? raw.slice(3) : raw
-
-        return v2RouteName(base, nodePath)
+        // v2RouteName is the single authority for the /v2 name rule,
+        // including de-duping the `v2-` that getPascalCaseRouteName
+        // already folds in from the routesFolder URL prefix.
+        return v2RouteName(raw, nodePath)
       },
     }),
     vue(),