TypedPython: remove the '# typedpython: compiled' module pragma; @compiled is the only mark #353

The maintainer decided (2026-10-03) that functions are marked with the builtin @compiled. The first-line # typedpython: compiled module pragma was added by an agent and never approved. Maintainer, 2026-10-30: keep only @compiled.

Scope: frontend/pipeline/main stop recognising the pragma (it becomes an ordinary comment); tests, the Kotlin-bridge fixture, benchmarks, the release example kernels.py, SPEC N-8 and docs/design/typedpython.md use @compiled instead.

Done when: no 'typedpython: compiled' left in the repository, and the TypedPython pytest suite passes (macOS locally, all OSes on the develop CI).