fix(website): SEO canonicals, host redirects, sitemap, app noindex

Addresses the high-volume issues from the Ahrefs audit:
- Worker entrypoint 301s every request not on https://paseo.sh
  (www subdomain and http variants), killing the duplicate-page
  errors and the HTTP→HTTPS internal-link notices.
- pageMeta() emits <link rel="canonical"> and og:url per route;
  every head() call now passes its canonical path.
- /blog stops rewriting itself to /blog?drafts=false; the search
  param only appears when explicitly true.
- Sitemap includes /blog and each post.
- Trim homepage title under SERP truncation, rewrite /agents meta
  description under 160 chars, pad short descriptions on
  /privacy, /download, /cloud, /changelog, /docs.
- app.paseo.sh gets <meta robots=noindex,nofollow> and a
  Disallow-all robots.txt so the SPA shell stops polluting the
  crawl with H1-missing / no-OG / low-word-count warnings.

packages/website/wrangler.toml

@@ -2,7 +2,7 @@ name = "paseo-website"
 account_id = "10ed39a1dbf316e30abd0c409bed40d6"
 compatibility_date = "2024-12-01"
 compatibility_flags = ["nodejs_compat"]
-main = "@tanstack/react-start/server-entry"
+main = "./src/server-entry.ts"
 
 routes = [
   { pattern = "paseo.sh", custom_domain = true },