chore: add dual MIT/Apache-2.0 licence

[jacderida]

Linear issue

V2-849 (rollout) / V2-850 (the licensing decision)

Risk tier

• T0 — docs / tooling / CI / pure UX-output. Repo CI only.
• T1 — client-only, no network-facing behavior change. CI + prod compat smoke.
• T2 — node/client logic with behavioral surface, no protocol/format/economics change. Dev testnet + ADR.
• T3 — protocol / storage format / payments / routing. T2 evidence + adversarial testing.

Compatibility

• Wire: none
• Storage: none
• API: none

Semver impact

• breaking
• feature
• fix

Test evidence

No code changed. This adds licence files only and a license field in package.json, so there is nothing to build or test. Verified both files are present at the repo root and correctly named.

New dependency

none

ADR

n/a

Mitigation / rollback

Revert the PR. Nothing depends on these files at build or run time, so reverting restores the previous state in a single commit.

What changed

This repository had no licence file. A public repo without one is not open source — under default copyright it is "all rights reserved", and GitHub's terms grant visitors only the right to view and fork within GitHub. No right to use, modify or distribute.

This adds LICENSE-MIT and LICENSE-APACHE at the repo root, copyright The Autonomi Foundation S/A.

Also sets "license": "MIT OR Apache-2.0" in package.json, which had none.

---

The reason for using MIT/Apache-2.0 and moving away from GPL 3.0 is purely allowing anyone to build anything from our code, even proprietary etc. if we are GPL we insist their projects must be GPL as well.

Bottom line, builders want it.

Per-file copyright attributions were left as they are throughout — they record who held copyright when the code was written. Only the licence grant text changed.

[jacderida]

Merging this without waiting for an approving review.

The decision to move to dual MIT OR Apache-2.0 has already been confirmed and is recorded on V2-850, along with the reasoning — we want people to be able to build anything on our code, including proprietary work, which copyleft prevents. The copyright holder (The Autonomi Foundation S/A) was confirmed at the same time.

This PR is one of 17 applying that decision across the org. There is no code change to review: licence files, package metadata, and licence-grant comment headers only. The substantive question here was the licensing choice itself, and that has been settled off the PR rather than in it.

Flagging it explicitly so the merge without a review is on the record rather than looking like an oversight.