Pin rgb-lib contract import revision

[Jainakin]

Purpose

Make the contract-only RGB import API from UTEXO-Protocol/rgb-lib#68 available to RGB Lightning Node without introducing a second rgb-lib revision into the Lightning dependency graph.

Changes

• pin lightning to rgb-lib commit 95332c41fd715939ac6e078ad859d474b1f6fa9b
• pin lightning-invoice to the same exact revision
• no Lightning protocol or runtime behavior changes

Keeping both crates on one immutable rgb-lib revision prevents duplicate RGB types and makes the downstream build reproducible while the dependency chain is reviewed.

Validation

Validated at 7af50e9482a6f2c681fd22002403be06576b3ff9.

• cargo check -p lightning -p lightning-invoice
• GitHub Actions: stable/beta build matrix on Linux, macOS, and Windows is green
• rustfmt, lint, and CodeQL are green

Merge order

1. Merge UTEXO-Protocol/rgb-lib#68.
2. Replace the review commit pin with the merged rgb-lib dev commit if the merge strategy rewrites the SHA.
3. Merge this PR.
4. Advance the rust-lightning submodule in UTEXO-Protocol/rgb-lightning-node#128 to the resulting dev commit.