[badrisatyam1-ctrl]

Closes #576

Make Dockerfile FROM matching case-insensitive and tolerant of leading indentation while keeping comments ignored.

Validation: git diff --check passed; Node tests unavailable locally.

[vibgrate-team]

Thanks so much for picking up #576, @badrisatyam1-ctrl, and for keeping the change nice and small.

It turns out this one is already covered elsewhere, so we won't take it forward separately:

• Docker FROM change: fix(docker): read lowercase and indented FROM instructions #591 makes the same fix (case-insensitive, indented FROM lines) and adds tests for it. It's already in review, so we'll land the fix through that one.
• Dart caret commit: this was stacked on from your earlier branch, and it's already on main via your merged fix(dart): parse caret SDK constraints #590. Thanks again for that one!

If you'd like another one to work on, there are open good first issue tickets we'd love help with. Starting each fix on a fresh branch from the latest main will keep older commits out of the diff. Really appreciate you contributing to Vibgrate.