perf: skip dry-run build for build --list

[krystophny]

Summary

• Return from fpm build --list after printing the target paths
• The old path printed target paths, then called
  build_package(..., dry_run=.true.); list mode does not need build graph
  sorting after the target list is already available
• --show-model still prints the model when requested

Merge order

Independent PRs (any order):

• Native is_dir (perf: use native directory checks on Unix #1291)
• Native mkdir (perf: create Unix directories without shell #1292)
• Build only selected run targets (perf: build only selected run targets #1293)
• Skip dry-run for run/test --list (perf: skip dry-run build for run --list and test --list #1294)
• Skip dry-run for build --list (perf: skip dry-run build for build --list #1295)
• Serialize pretty-mode progress under OpenMP (fix: serialize pretty-mode build progress output under OpenMP #1296)
• Dependency-driven build scheduler (feat: dependency-driven build scheduler (no per-region barrier) #1297)

Stacked chain (merge in order):

1. Fortran compiles via argv (feat: exec Fortran compiles via argv (posix_spawn/CreateProcess) #1299)
2. Parallel link/archive via argv (feat: run link and archive in parallel via argv spawn #1300)
3. C/C++ compiles via argv (feat: exec C/C++ compiles via argv, close the shell-fork gap #1301)

Fork-safety fix:

• Serialize mkdir on run_command lock (fix: serialize mkdir shell fork on the run_command lock #1298)

After the above:

• Interface-aware rebuild (Skip recompiling dependents when a module interface is unchanged (gfortran) #1289, already open)
• Enable default features via manifest (pending CI fix)

Verification

$ fpm build --features openmp --compiler gfortran --flag '-O3 -g'
[100%] Project compiled successfully.

$ fpm test
TALLY;TTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTT
PASSED: all 35 tests passed

Benchmark (fpm self build --list, median of 3):

parallel: 0.59s main, 0.39s branch, 0.20s faster, 33.9%
serial:   0.45s main, 0.40s branch, 0.05s faster, 11.1%

Target list is identical after normalizing the build-dir prefix.