Implement direct-entrypoint route without an adapted fortran bridge

[saidctb]

• Added a native-entrypoint adoption roadmap for selective direct Fortran
  bind(C) calls and the initial direct-only C wrapper backend, including
  conservative starter-contract defaults for ambiguous C pointers.
• Added @native_abi("c") to semantic .pyi contracts so Fortran bind(C)
  procedures retain their ABI and optional link label through generated and
  source-free contract workflows.
• Added a separate direct-entrypoint PRIK/f2py runtime and clean-build benchmark
  cohort with untimed correctness, generated-source membership, and linked
  direct-symbol preflight, plus an ordinary-Fortran PRIK control.

[codecov]

Codecov Report

❌ Patch coverage is 84.74240% with 231 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
prik/pipeline/wrapper.py	59.04%	47 Missing and 82 partials ⚠️
prik/policy/construction.py	74.05%	36 Missing and 19 partials ⚠️
prik/planning/entrypoints.py	93.65%	13 Missing and 12 partials ⚠️
prik/semantics/pyi2ir.py	84.50%	6 Missing and 5 partials ⚠️
prik/planning/planner.py	96.36%	1 Missing and 3 partials ⚠️
prik/printers/pyi.py	89.74%	2 Missing and 2 partials ⚠️
prik/pipeline/build.py	85.71%	0 Missing and 1 partial ⚠️
prik/policy/native_array_handles.py	96.15%	1 Missing ⚠️
prik/semantics/models.py	97.43%	0 Missing and 1 partial ⚠️

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