fix: inject release tag version into binary

[bcho]

What changed

• Allow B4FUN_AI_VERSION to override the package version in standalone SEA builds.
• Derive release build versions from tags such as v0.2.0.
• Verify release binaries report the tag-derived version.
• Keep local builds defaulting to the version in package.json.

Why

The v0.2.0 release assets were built from a package still declaring 0.1.2, so ai upgrade downloaded the latest asset but the installed binary continued to report 0.1.2.

Validation

• npm test
• npm run check
• B4FUN_AI_VERSION=0.2.0 npm run build:sea and dist/sea/ai --version reports 0.2.0
• npm run build:sea and dist/sea/ai --version reports package version 0.1.2