fix: Handle splat/catch-all routes in URL pattern matching

A bare `$` segment matches multiple path segments (e.g., `/files/$`
matches `/files/a/b/c`).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: nicohrubec

packages/tanstackstart-react/src/server/routeParametrization.ts

@@ -9,6 +9,9 @@ function patternToRegex(pattern: string): RegExp {
   const segments = pattern
     .split('/')
     .map(segment => {
+      if (segment === '$') {
+        return '.+';
+      }
       if (segment.startsWith('$')) {
         return '[^/]+';
       }

packages/tanstackstart-react/test/server/routeParametrization.test.ts

@@ -41,4 +41,16 @@ describe('matchUrlToRoutePattern', () => {
     const patternsNested = ['/users/$id', '/users/$id/profile'];
     expect(matchUrlToRoutePattern('/users/123/profile', patternsNested)).toBe('/users/$id/profile');
   });
+
+  it('matches splat/catch-all routes across multiple segments', () => {
+    const patternsWithSplat = ['/', '/files/$'];
+    expect(matchUrlToRoutePattern('/files/a/b/c', patternsWithSplat)).toBe('/files/$');
+    expect(matchUrlToRoutePattern('/files/readme.txt', patternsWithSplat)).toBe('/files/$');
+  });
+
+  it('prefers specific routes over splat routes', () => {
+    const patternsWithSplat = ['/files/$', '/files/upload'];
+    expect(matchUrlToRoutePattern('/files/upload', patternsWithSplat)).toBe('/files/upload');
+    expect(matchUrlToRoutePattern('/files/a/b', patternsWithSplat)).toBe('/files/$');
+  });
 });