docs: add DACS Forge to community index

[mj-deving]

Summary

Adds DACS Forge to the Community index as an external Bun/TypeScript reference implementation.

The entry:

• identifies its implemented DACS v0.4 lifecycle surfaces;
• limits vector-tested to the named vector families exercised by the repository;
• points readers to the immutable fixture/no-spend v0.1.1 Product Seal and exact-tag run path;
• states the MIT license and that no secrets are required.

Boundaries

This catalogue entry is not a live Directory registration, canonical designation, certification, endorsement, full-conformance claim, production deployment, or live-commerce qualification.

Verification

• Fresh Linux clone of v0.1.1 with Bun 1.3.9: frozen install passed; 1,072 tests and 60,935 expectations passed; build passed.
• All four external links in the new row returned HTTP 200.
• GitHub's Markdown renderer produced the expected six-column row.
• git diff --check passed.

Only INDEX.md changes.