Add Miri testing for unsafe code validation

[RAprogramm]

Closes #26

Changes

Added Miri testing workflow for validating all unsafe code in the library.

Workflow Configuration

Created .github/workflows/miri.yml with:

• Runs on push/PR to main branch
• Weekly scheduled runs (Mondays at 03:00 UTC)
• Uses Rust nightly with Miri component
• Rust cache for faster builds
• MIRIFLAGS for enhanced checks:
  • -Zmiri-symbolic-alignment-check - validates pointer alignment
  • -Zmiri-disable-isolation - allows system interactions in tests

Unsafe Code Validated

Miri validates all unsafe code in:

• src/array.rs:84 - Pointer operations in pointer array construction
• src/array.rs:162-163 - Raw pointer dereferencing in as_ptr
• src/array.rs:187-189 - Mutable pointer operations
• tests/integration.rs - Extensive unsafe FFI testing
• Send/Sync implementations

Test Results

All tests pass under Miri without errors:

• 34 unit tests
• 11 integration tests
• 17 doctests
• Total: 62 tests

Benefits

• Soundness: Mathematically proves unsafe code is correct
• UB Detection: Finds undefined behavior at compile time
• Confidence: Validates pointer operations and FFI safety
• Professional: Industry-standard validation for unsafe code
• FFI Safety: Critical for C interop libraries
• Continuous Monitoring: Weekly scheduled runs catch regressions

Testing

• Tested locally: cargo +nightly miri test --all-features
• All 62 tests pass without Miri errors or warnings
• Workflow will run on every PR and weekly

References

• Miri Documentation: https://github.com/rust-lang/miri
• Rust Unsafe Code Guidelines: https://rust-lang.github.io/unsafe-code-guidelines/

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ All tests successful. No failed tests found.

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