fix(web): add trailing slash to base path — fixes broken navigation URLs

All internal links were missing a / between the base path and route:
/us-code-trackerbrowse/ instead of /us-code-tracker/browse/

Root cause: astro.config.mjs base was '/us-code-tracker' (no trailing
slash). Astro's BASE_URL concatenated without separator.

Fix: base: '/us-code-tracker/' (with trailing slash)

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

Author: williamzujkowski

apps/web/astro.config.mjs

@@ -6,5 +6,5 @@ export default defineConfig({
   integrations: [svelte()],
   vite: { plugins: [tailwindcss()] },
   site: 'https://civic-source.github.io',
-  base: '/us-code-tracker',
+  base: '/us-code-tracker/',
 });