feat(trustlab): add SEO support for organisations

[kilemensi]

Description

Summary

• Pathname hook: adds appendPathnameToCollection afterRead hook to Organisations, giving each doc a computed pathname (e.g. /organisations/some-org) — the foundation for correct canonical URLs and sitemap entries
• SEO plugin: registers organisations with the Payload SEO plugin so editors get meta title/description/image fields in the admin UI; fixes generateTitle to fall back to doc.name (orgs don't have a title field) and generateURL to use doc.pathname
• Sitemap: adds getOrganisationsEntries — only orgs with includeLink: true and linkType: "internal" are included, as those are the ones with a TrustLab detail page
• Pagify: normalises the title field in pagifyOpportunities via doc.title || doc.name so organisation pages get a title for the <title> tag and canonical URL logic

Test plan

• Organisation detail page renders with correct <title> and meta description
• Canonical URL is /organisations/[slug], not just /[slug]
• Payload admin SEO tab for an organisation shows a non-empty generated title (pulled from name)
• /sitemap.xml includes organisations with linkType: "internal"
• Organisations with linkType: "custom" or includeLink: false are absent from the sitemap

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

Screenshots

SEO Title

Sitemap

  <url>
    <loc>http://localhost:3000/opportunities/organisations/dhamira-moja-cbo</loc>
    <lastmod>2026-07-01T06:31:43.212Z</lastmod>
  </url>
  <url>
    <loc>http://localhost:3000/opportunities/organisations/ajenda-kenya</loc>
    <lastmod>2026-07-01T06:35:34.716Z</lastmod>
  </url>
  <url>
    <loc>http://localhost:3000/opportunities/organisations/africa-youth-trust</loc>
    <lastmod>2026-07-01T06:34:08.921Z</lastmod>
  </url>
  <url>
    <loc>http://localhost:3000/opportunities/organisations/inuka-community-developers-network</loc>
    <lastmod>2026-07-01T06:30:45.043Z</lastmod>
  </url>
  <url>
    <loc>http://localhost:3000/opportunities/organisations/lamu-arts--theatre-alliance</loc>
    <lastmod>2026-06-30T14:10:10.826Z</lastmod>
  </url>

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas