Fix Builder MP SEO: noindex auth pages, promote bills listing

[xrendan]

Summary

Searching "Builder MP" on Google returns /bills/sign-in ranked above the bills listing.

Root cause: the sign-in page had no metadata, so it inherited the bills layout default title "Builder MP" verbatim. The listing itself was titled "Home · Builder MP", which Google rewrote to the H1 "45th Canadian Federal Parliament".

Changes

• noindex, nofollow on /bills/sign-in, /bills/unauthorized and /bills/[id]/edit (layouts added where the page is a client component)
• Bills listing: absolute title "Builder MP — Canadian Federal Bills Tracker | Build Canada", Builder MP-led description, keywords, and WebApplication JSON-LD naming Build Canada as publisher
• Listing H1 now "Builder MP: Bills of the 45th Canadian Parliament" with a subtitle
• Layout default / Twitter descriptions mention Builder MP
• /bills sitemap priority 0.8 → 0.9; /bills/api/ added to robots disallow

Sign-in is intentionally not added to robots disallow: Google must crawl it to see the noindex tag.

Testing

• tsc --noEmit and eslint pass
• After deploy: request re-indexing of /bills and /bills/sign-in in Search Console

[greptile-apps]

Confidence Score: 5/5

The PR appears safe to merge, with no outstanding correctness or repository-rule violations identified.

Summary

This PR improves Builder MP search presentation and prevents authentication and editing routes from being indexed.

• Adds noindex, nofollow metadata to sign-in, unauthorized, and bill-editing pages.
• Gives the bills listing a stronger title, description, keywords, heading, and WebApplication structured data.
• Disallows the bills API route in robots.txt and raises the listing’s sitemap priority.
• Simplifies the newly added listing copy to consistently use “builder-first.”

_{Reviews (2) · Last reviewed commit: "Simplify Builder MP copy"}

Dismissed because a newer commit was pushed; Greptile will re-review the current head.