chore: engine dep from npm — interscript@^3.0.0

[ronaldtse]

Summary

• the engine dependency comes from the registry: interscript@^3.0.0 (the new bare-name TS runtime); imports and docs examples updated to the new package name
• repo-path references (status page's interscript-ts/scripts/full-parity.rb) unchanged — the repo is still interscript-ts

Test plan

• 255/255 tests, check/lint/format/build green
• CI no longer needs the interscript-ts sibling clone (kept for maps catalogue only if still required)