Audit and improve SEO across my entire web app.

Stack:
- Frontend: Svelte
- Backend: Python
- I currently cannot see proper <title> tags and likely have weak or missing meta tags
- Goal: improve technical SEO on every page without changing the visual design or breaking functionality

What I need you to do:
1. Inspect the frontend routing/pages/components and identify how page-level head metadata is currently handled.
2. Add proper SEO metadata to every user-facing page.
3. Ensure each page has:
   - a unique <title>
   - a unique meta description
   - canonical URL where appropriate
   - Open Graph tags
   - Twitter card tags
   - robots directives where needed
4. If this is plain Svelte, use <svelte:head> correctly in each page/component.
5. If this project is SvelteKit, use the proper page/layout pattern for reusable SEO handling and page-specific overrides.
6. Create a reusable SEO component or helper so metadata is not duplicated everywhere.
7. Make sure the default site-wide metadata can be overridden per page.
8. Add sensible fallbacks for:
   - site name
   - default description
   - default social image
   - canonical base URL
9. Ensure the home page, pricing page, about page, contact page, blog pages, service pages, and any marketing landing pages have strong page-specific metadata.
10. Ensure admin, dashboard, account, login, test, preview, internal, or private pages are marked noindex where appropriate.
11. Check whether the app is rendered in a way search engines can read:
   - If SvelteKit, verify SSR/prerender strategy where relevant
   - If SPA-only Svelte, note the SEO limitations clearly and still implement best-possible head tags
12. Add or improve:
   - sitemap.xml generation
   - robots.txt
   - structured data / JSON-LD where relevant (Organisation, LocalBusiness, Website, BreadcrumbList, Article if applicable)
13. Make sure all metadata uses clean absolute URLs, not broken relative paths.
14. Verify there are no duplicate titles/descriptions across major pages.
15. Keep implementation simple, maintainable, and production-ready.

Important constraints:
- Do not redesign the UI
- Do not change backend business logic unless needed for SEO output
- Do not add large dependencies unless clearly justified
- Prefer native Svelte / SvelteKit patterns
- Keep code clean and minimal
- If assumptions are needed, make reasonable ones and proceed

Deliverables:
- Implement the SEO improvements directly in code
- Show me all changed files
- Explain the SEO architecture briefly
- Point out any pages that still have SEO limitations
- Flag whether this project is plain Svelte SPA or SvelteKit, and explain the impact on SEO

Also check for these common issues:
- missing <title>
- missing meta description
- duplicate metadata
- missing og:image
- missing canonical
- incorrect robots directives
- pages hidden from crawlers accidentally
- client-only rendering issues
- missing sitemap / robots.txt
- no structured data

Use current best practices for Svelte SEO.