fix(license): repair the 404 license link, and make GitHub detect MIT

[ndemianc]

The report

https://github.com/levelcodeai/levelcode/blob/main/LICENSE returns 404.

Two root causes (the second found while fixing the first)

1. The link pointed at a branch that doesn't exist. branding/product.overlay.json hardcoded licenseUrl/serverLicenseUrl to /blob/main/LICENSE, but there is no main branch — the default is develop. So the license link baked into the app's About / license metadata 404'd. The LICENSE file itself was fine and present all along.

Fixed to /blob/HEAD/LICENSE. GitHub resolves HEAD to whatever the default branch is, so it works on develop today and survives a future rename to main — no branch has to be created.

2. GitHub wasn't detecting the license as MIT. While verifying, the license API reported:

GET /repos/levelcodeai/levelcode/license  ->  spdx_id: NOASSERTION

NOASSERTION means the detector couldn't classify the file — so the repo carried no "MIT License" label. Cause: the derivative / Microsoft-trademark paragraph appended after the MIT text pushed the file below licensee's template-match threshold.

Fixed the way upstream VS Code does it — LICENSE is now verbatim MIT (the grant and the copyright line are byte-for-byte unchanged; see the diff — only the trailing block was removed), and the Code-OSS provenance + trademark disclaimer move to a dedicated NOTICE file. The README's License section now points at both. Nothing is lost, and MIT will detect once this lands on the default branch.

Commits

• d9755a6 — product license URL main → HEAD (the 404 fix)
• cbf4f4f — LICENSE → pure MIT, attribution → new NOTICE, README pointer

Verification

• product.overlay.json still parses as JSON; both ?ref=HEAD and ?ref=develop serve LICENSE.
• LICENSE diff removes only the appended block — the MIT terms and Copyright (c) 2026 Sergii Demianchuk (LevelCode) are untouched.
• NOTICE is plain ASCII.

Kept intentionally separate from the pending RELEASE-NOTES.md v1.0.0 change.

🤖 Generated with Claude Code

[Copilot]

Pull request overview

This PR fixes LevelCode’s license metadata and repository license hygiene so the in-app license link no longer 404s (independent of default-branch name) and GitHub can correctly classify the repository as MIT.

Changes:

• Update product metadata license URLs to use blob/HEAD/LICENSE instead of a hardcoded main branch.
• Restore LICENSE to a verbatim MIT License text to satisfy GitHub/licensee detection.
• Move derivative/trademark/provenance language into a new NOTICE file and link it from the README.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
README.md	Updates the License section to reference both LICENSE and the new NOTICE for attributions.
NOTICE	Adds a dedicated notice file for derivative/trademark/provenance statements removed from LICENSE.
LICENSE	Removes the appended non-MIT block so the file is pure MIT (improves GitHub license detection).
branding/product.overlay.json	Fixes licenseUrl/serverLicenseUrl to use HEAD to avoid default-branch 404s.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.