docs: add CONTRIBUTING.md and FUNDING.yml

Aligns the project website repo with the rest of the HTMLTrust
ecosystem. No README appendix here because the website doesn't have a
repo-level README — the equivalent "Origin & Contributions" content
lives in the site's About / FAQ pages as user-facing content.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: jt55401

.github/FUNDING.yml

@@ -0,0 +1,9 @@
+# GitHub Sponsors (primary)
+github: [jt55401]
+
+# Secondary channels
+custom:
+  - https://paypal.me/jt55401
+  - https://venmo.com/Jason-Grey-1
+  - bitcoin:1CJDZEJD86viU1L3kewMmXyx7VyPNcwzB9
+  - ethereum:0xbC1240fe5F8e0732F7A0daA132a30982459Af5b3

CONTRIBUTING.md

@@ -0,0 +1,50 @@
+# Contributing
+
+Thanks for helping move HTMLTrust forward.
+
+## Contribution Flow
+
+1. Fork the repository.
+2. Create a branch for your change.
+3. Run the project's existing checks (tests, linters, conformance vectors —
+   see the README for the specific commands).
+4. Open a pull request against `main`.
+
+For larger changes (a new resolver, a new normalization phase, a new spec
+section), open an issue first to talk about scope. Saves everyone time.
+
+## What's in scope
+
+- Code, tests, and conformance vectors that improve any of the reference
+  implementations.
+- Spec clarifications, examples, and edits that fix ambiguity.
+- Bug fixes, security fixes, performance improvements.
+- New language bindings of the canonicalization library that pass the
+  conformance suite.
+
+## What's out of scope
+
+HTMLTrust is a mechanism, not a value judgment. The project does **not**
+accept contributions or issues for:
+
+- Debates over whether AI should or shouldn't be used to author software or specifications.
+- Lists of "approved" vs "disapproved" signers.
+- Political, religious, or philosophical positions on what content should be trusted.
+- Trust directory operator policies — those belong to the directory operators.
+
+The protocol is deliberately neutral so anyone can sign anything they
+publish and any user can decide for themselves whom to trust. If you want
+to debate the answers, that's a different project.
+
+## Legal and Attribution
+
+- By submitting a contribution, you agree your change is provided under the
+  repository's license (`PolyForm-Noncommercial-1.0.0` for code repos,
+  `CC-BY-NC-ND-4.0` for the spec and website).
+- Keep existing copyright, license, and notice text intact.
+- AI-assisted contributions are fine. If the contribution is substantial,
+  briefly disclose the tools used in the PR description.
+
+## Code of Conduct
+
+Be technical. Be precise. Don't waste people's time.