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/src/plugins/1.router/__tests__/v2RouteName.spec.ts

@@ -12,11 +12,23 @@ describe('v2RouteName', () => {
     expect(v2RouteName('index', 'v2/')).toBe('v2-index')
   })
 
+  it('de-dups when the raw name already folded in the v2 segment', () => {
+    // getPascalCaseRouteName folds the /v2/ URL prefix into the base, so
+    // the raw name arrives as `v2-dashboard`; the result must still be a
+    // single `v2-dashboard`, never `v2-v2-dashboard`.
+    expect(v2RouteName('v2-dashboard', '/v2/dashboard')).toBe('v2-dashboard')
+    expect(v2RouteName('v2-events-id', '/v2/events/:id')).toBe('v2-events-id')
+  })
+
   it('leaves v1 route names untouched', () => {
     expect(v2RouteName('dashboard', '/dashboard')).toBe('dashboard')
     expect(v2RouteName('events', '/events')).toBe('events')
   })
 
+  it('does not strip a v1 name that starts with v2- when the path is not under /v2', () => {
+    expect(v2RouteName('v2-legacy', '/v2-legacy')).toBe('v2-legacy')
+  })
+
   it('does not match a v1 path that merely starts with the letters v2', () => {
     expect(v2RouteName('v2x-thing', '/v2x-thing')).toBe('v2x-thing')
   })

apps/app/src/plugins/1.router/v2RouteName.ts

@@ -1,20 +1,30 @@
 /**
  * Route-NAME collision guard for the parallel /v2/* tree.
  *
- * unplugin-vue-router derives the route name from the file path relative
- * to its routesFolder, so `src/pages/events/index.vue` and
- * `src/pages-v2/events/index.vue` would BOTH yield name `events` — a
- * silent runtime collision (router.push({ name: 'events' }) becomes
- * ambiguous). The pages-v2 routesFolder carries `path: 'v2/'`, so every
- * v2 route's URL path is under `/v2`. Prefix the NAME with `v2-` for
- * those, leaving v1 names untouched. Stripped at final cutover.
+ * unplugin-vue-router derives the route name from the file path. With a
+ * second routesFolder mounting `src/pages-v2` under URL prefix `/v2/`,
+ * `getPascalCaseRouteName` folds that `v2` segment into the base name
+ * (e.g. `/v2/dashboard` → `v2-dashboard`), while a same-named v1 page
+ * under `src/pages` yields a bare `dashboard` — a silent runtime name
+ * collision. This helper is the SINGLE authority for the v2 name rule:
+ * for any route whose path is under `/v2`, normalise to exactly one
+ * canonical `v2-` prefix (stripping the prefix the pascal name already
+ * folded in, then re-adding it); v1 names pass through untouched.
+ * Reverted at final cutover.
  *
- * @param baseName  the kebab name already computed by getRouteName
+ * @param rawName   the kebab name computed by getRouteName
  * @param routePath the node's URL path (leading slash optional)
  */
-export function v2RouteName(baseName: string, routePath: string): string {
+export function v2RouteName(rawName: string, routePath: string): string {
   const normalized = routePath.replace(/^\//, '')
   const isV2 = normalized === 'v2' || normalized.startsWith('v2/')
 
-  return isV2 ? `v2-${baseName}` : baseName
+  if (!isV2)
+    return rawName
+
+  const base = rawName.startsWith('v2-')
+    ? rawName.slice('v2-'.length)
+    : rawName
+
+  return `v2-${base}`
 }

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(),