feat: engine dep from npm — vendor snapshot removed (1.1.0)

[ronaldtse]

Summary

• the engine dependency comes from the registry now: interscript@^3.0.0 (the new TS ISC runtime, published under the org's bare npm name)
• the 278-file vendor/interscript-ts snapshot is deleted; lockfile resolves interscript@3.0.0 from npm
• 1.1.0

Test plan

• 25/25 tests, typecheck/lint/format/build green
• package guard: code-only, 24.6KB packed
• parity e2e on staging after deploy