chore(license): relicense MIT → AGPL-3.0-only · bump 3.0.0 → 3.0.1

[kengio]

Summary

Align the plugin's license with the OneBrain CLI (onebrain-ai/onebrain-cli), which has shipped under AGPL-3.0-only since v3.0.0-alpha.0. Same license now spans:

• The Rust CLI binary (onebrain)
• Plugin manifest / skills / hooks that drive the binary
• The forthcoming Homebrew tap formula and npm wrapper

so AGPL §13's network-use copyleft applies consistently across the OneBrain runtime stack.

Changes

File	Change
LICENSE	21-line MIT → 661-line canonical GNU AGPL v3
plugin.json	add "license": "AGPL-3.0-only" field
plugin.json	bump 3.0.0 → 3.0.1 (manifest change ⇒ version bump per repo convention)
PLUGIN-CHANGELOG.md	v3.0.1 entry (6 bullets)

No skill / hook / agent code changes. Purely license + manifest update.

MIT compatibility

Past plugin releases (v2.x through v3.0.0) remain available under MIT for downstream users who pinned to those versions — license grants are perpetual, can't be retroactively revoked. AGPL applies from v3.0.1 forward.

Why now

User explicitly requested alignment in response to today's CLI v3.0.0 GA. Doing it as a fast follow-on so v3.0.x's distribution channels (Homebrew tap, npm wrapper, GH Releases) all match the plugin's declared license from the start of the v3.x lifecycle.

Test plan

• LICENSE file is the unmodified GNU AGPL v3 text (fetched from onebrain-ai/onebrain-cli/main/LICENSE).
• plugin.json is valid JSON with the new license and bumped version fields.
• PLUGIN-CHANGELOG follows the repo's max-8-bullets-per-version style.
• GitHub repo metadata picks up the new license (no API call needed — GitHub re-scans on the next push).
• 3-round parallel review (correctness · behavior · security) — light review since the change is metadata + LICENSE swap.