[audit/critical] Add LICENSE file

[Displacedtex]

Priority: Critical

Problem

No LICENSE file is committed. Without one, GitHub's default ("All rights reserved") applies — fork/reuse is technically not permitted, contradicting the README's "continuously updated... take pull requests" framing.

Recommendation

For a curated link list, pick one of:

• CC-BY-4.0 — attribution required; conventional for awesome-lists.
• MIT — simple, permissive, common for curated content.
• CC0-1.0 — public domain dedication; most permissive.

Acceptance criteria

• LICENSE file at repo root.
• README footer references the license choice.

Part of the repo audit backlog.