docs: README and site links for HarnessMD/munder-difflin

[chaitanyagiri]

What & why

The public repo moved to the HarnessMD organisation. This points the README and the site at the real address instead of a redirect, and adds a link row and a first paragraph that say what the project is. Markdown, HTML and the blog source only. No app code.

• README: a link row under the title (Website, Download, Discord, Contributing). The first paragraph keeps "Free, open source and performant" and now names the agent harness, Claude Code, Codex and the ten other engines in the README's own Supported agents list. All 12 owner links now point at HarnessMD, badges included. The 6 mentions that mean the current release go from 0.5.3 to 0.5.5: the version badge, the download line, three release links and "builds of". The 6 that date a feature stay at 0.5.3, because those features shipped in 0.5.3.
• docs/ and blog/src: chaitanyagiri/munder-difflin becomes HarnessMD/munder-difflin, on URLs only, in 364 files. blog/src changes too, so the next blog build does not undo docs/blog.
• Not touched: docs/hires, docs/hero.json and docs/model-catalog.json, which the shipped app reads. That change goes in 0.5.6 with its own test. docs/r is also left alone.
• CONTRIBUTING.md: the dead #what-gets-a-pr-closed anchor now goes to #where-the-bar-is, and "Questions" links to Discussions and Issues instead of ../../issues.
• Issue forms: the version placeholders move from 0.4.5 and 0.4.6 to 0.5.5.

Type of change

• Bug fix
• New feature
• Refactor / cleanup
• Docs
• Build / CI

Evidence

Before

After

How I tested it

• OS: macOS
• Steps:
  1. A script compared every changed line in docs/ and blog/src with its old line. 532 lines changed, and 0 of them differ by anything other than the owner string. No file changed its line count.
  2. A request to every unique URL on a changed line (81 URLs), following redirects: all 81 returned 200, including releases/tag/v0.5.5.
  3. npm run check:links: "release links consistent at v0.4.6".
  4. A grep of the diff for munder-difflin-pro: 0 hits. No file changed outside README.md, CONTRIBUTING.md, .github/ISSUE_TEMPLATE, docs/ and blog/src.
  5. Typecheck was not run locally (the worktree has no node_modules). CI runs Typecheck and Build on this PR.

Checklist

• Before and after evidence is attached above, under both headings.
• npm run typecheck passes. (CI)
• npm run test:focused passes. (no code changed)
• npm run build succeeds. (CI)
• This PR is one change: the address move and the README top.
• I read the diff myself before opening this.
• No new UI.
• No new art.

🤖 Generated with Claude Code