chore(repo): add feature request form

[vincentkoc]

What Problem This Solves

The repository baseline added a bug form but omitted the companion feature-request form used by the other TypeScript library repositories, leaving GitHub community health at 87%.

Why This Change Was Made

Adds a focused feature form for filesystem-safety API proposals, with explicit security and compatibility prompts.

User Impact

No package or runtime change. Contributors get a structured route for feature proposals.

Evidence

• YAML parsing passed

• git diff --check passed

• enhancement label exists

• Tests added or updated when behavior changed (no runtime behavior changed)

• Security and compatibility impact considered

• CHANGELOG.md updated when release-relevant (covered by the existing 0.4.6 repository-baseline entry)

• No credentials, private paths, private hosts, or sensitive contents included

[vincentkoc]

Addressed the ClawSweeper P2/rank-up move in ff5fcb9: the feature form now links directly to the repository private security-advisory submission page. YAML parsing, link resolution, CodeQL, and the full cross-platform CI matrix pass on the fix head.