feat: add F command

[MukundaKatta]

Summary

• add GNU sed's F command outside POSIX mode
• track a raw input filename separately from the quoted error-context name
• cover file input, stdin, NUL-terminated output under -z, and POSIX rejection

Fixes #393.

Tests

• cargo fmt --check
• cargo test pattern_print_filename_with_f_command
• cargo test test_sed
• cargo test
• cargo run --quiet -- -n 'F' tests/fixtures/sed/input/lines1 | head -n 3

[codecov]

Codecov Report

❌ Patch coverage is 12.50000% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 82.09%. Comparing base (f083fa0) to head (677e524).

Files with missing lines	Patch %	Lines
src/sed/compiler.rs	0.00%	4 Missing ⚠️
src/sed/processor.rs	0.00%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #429      +/-   ##
==========================================
- Coverage   82.20%   82.09%   -0.12%     
==========================================
  Files          13       13              
  Lines        5542     5550       +8     
  Branches      310      312       +2     
==========================================
  Hits         4556     4556              
- Misses        983      991       +8     
  Partials        3        3              

Flag	Coverage Δ
macos_latest	82.77% <12.50%> (-0.13%)	⬇️
ubuntu_latest	82.87% <12.50%> (-0.13%)	⬇️
windows_latest	0.00% <0.00%> (ø)

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[codspeed-hq]

Merging this PR will degrade performance by 5.62%

⚠️ Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

Open the report in CodSpeed to investigate

⚡ 1 improved benchmark
❌ 1 regressed benchmark
✅ 9 untouched benchmarks

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Benchmark	BASE	HEAD	Efficiency
⚡	genome_subst	215.5 ms	209.8 ms	+2.7%
❌	number_fix	517.8 ms	597 ms	-13.26%

Tip

Investigate this regression by commenting @codspeedbot fix this regression on this PR, or directly use the CodSpeed MCP with your agent.

---

_{Comparing MukundaKatta:codex/add-f-command (677e524) with main (f083fa0)}

[dspinellis]

Thanks! Please address the comments, rebase, squash, and ask for another review.

[dspinellis]

I see no reason for a second name.

[dspinellis]

It think this should now be OsString (see other examples in the code).Using - rather than <stdin> is OK.