chore(community): add SUPPORT.md, CODEOWNERS, .gitattributes, dependabot, Docker exemptions

[OneByJorah]

Summary

Adds the community and governance files required by the OneByJorah modernization directive:

• SUPPORT.md — support channels and self-hosting guidance.
• CODEOWNERS — default owner @OneByJorah + review gates for .github/, *.md, *.yml, .env.
• .gitattributes — linguist language correction + text eol=lf normalization + binary asset handling.
• dependabot.yml — weekly version updates (npm/pip/docker/github-actions as applicable) where missing.
• docs/DOCKER_EXEMPTION.md — written exemptions for repos with no runtime (HelpDeskForge, MSPEngine, OneByJorah, OneByJorah.github.io).

No runtime behavior changed. No secrets, no dependency version changes, no Dockerfile edits.

Security

No secrets or credentials introduced. .gitattributes marks binary assets as binary. CODEOWNERS adds review gating for .env and .github/ files. dependabot.yml adds weekly version-update checks where missing.

Testing

Static file addition only. No tests modified. Pre-existing CI (where present) runs against the default branch; this PR adds no new workflows.

Docker validation

Not applicable to this PR — no Dockerfile or compose file changed. Repos without a runtime have a written DOCKER_EXEMPTION.md on file.

Screenshots

Not applicable — no UI changes.

Rollback plan

• git revert on the feature branch, push, and close the PR.
• Alternatively, delete the feature branch; no default-branch changes were made.
• All changes are additive files only; rollback is a single commit revert per repo.

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Co-Authored-By: Codebuff noreply@codebuff.com