[codex] Prepare Pointer open-source release

[Samuel-Mencke]

Summary

Prepares Pointer for the first open-source Windows x64 release draft by cleaning public repo surfaces, hardening release automation, and moving local packaging to GitHub Actions.

• replaces Microsoft-centered public issue, PR, and security guidance with Pointer-specific templates
• aligns product/package/installer/support URLs to PointerIDE/Pointer
• adds launch checklist docs, CI metadata/secret/README checks, npm Dependabot, and draft-release workflow inputs
• updates vulnerable runtime dependencies and documents the remaining moderate upstream uuid advisory
• prunes non-target native Copilot/Claude payloads during Windows packaging so rcedit only stamps Windows-native binaries

Validation

• npm run compile-check-ts-native
• cd build && npm run typecheck
• npm audit --omit=dev --audit-level=high
• git diff --check
• product metadata check
• README image reference check
• high-confidence tracked secret scan

Local Windows release packaging was intentionally stopped because it was overloading this workstation. The updated Pointer Windows Release workflow should build Installer + ZIP on GitHub Actions instead.