Align community defaults with the MSX baseline #74

Context and request

Align the public PSModule/.github repository with the shared MSX organization-default baseline while preserving the PSModule public profile and optional GitHub templates.

Acceptance criteria

• PSModule/.github remains public, and its README defines the special repository role, public visibility requirement, repository-local precedence, and enforcement model.
• .github/CODE_OF_CONDUCT.md matches the complete official Contributor Covenant 3.0 Markdown except for the required support@psmodule.io reporting contact and removal of the authoring note before the published enforcement ladder.
• .github/SECURITY.md prefers private vulnerability reporting, falls back to security@psmodule.io, prohibits public vulnerability reports, and routes exposed sensitive information, exposed credentials, exposed secrets, and weak or unsafe security controls through the same private channels.
• .github/SUPPORT.md routes private support matters to support@psmodule.io and exposes no billing contact.
• Contribution guidance links to the MSX agent plugin marketplace and the PSModule process plugin.
• Shared repository baseline surfaces align with current MSX standards: README.md, AGENTS.md and client routes, .gitattributes, .gitignore, .github/CODEOWNERS, .github/dependabot.yml, .github/pull_request_template.md, .github/CODE_OF_CONDUCT.md, .github/CONTRIBUTING.md, .github/SECURITY.md, and .github/SUPPORT.md.
• AGENTS.md identifies PSModule/Process-PSModule, private PSModule/memory, and inherited MSXOrg/docs, including entry files, published documentation, and preferred organization-named clone locations.
• PSModule-specific profile content and optional issue, funding, and release surfaces remain intact.
• Markdown, YAML, links, GitHub metadata, upstream Covenant equivalence, contacts, placeholders, and the final diff pass validation.
• Copilot completes a clean review round or all findings are resolved with evidence.

Technical decisions

• Use 📖 [Docs]: Organization-wide community defaults established MSXOrg/.github#2 as the sibling implementation reference and the MSX Repository Standard as the shared authority.
• Use support@psmodule.io for conduct and private support matters and security@psmodule.io for private security reports.
• Preserve the complete Contributor Covenant 3.0 text and its CC BY-SA 4.0 attribution. Do not add a repository-level license.
• Preserve existing PSModule profile, issue-template, funding, and release surfaces because they are organization-specific capabilities rather than baseline differences.
• Agent routes identify repository sources and preferred organization-named clone locations without prescribing an access tool.
• Keep public prose evergreen, declarative, definitive, and written in simple en-US. The verbatim Contributor Covenant text is the only prose exception.

Implementation plan

• Record the shared baseline and validation assertions.
• Align repository governance, ownership, dependency, pull-request, line-ending, ignore, and agent-routing surfaces.
• Align conduct, contribution, security, and support guidance with organization-specific contacts.
• Complete targeted validation and GitHub metadata checks.
• Complete the explicit Copilot review loop and record the result.