fix: serialize pretty-mode build progress output under OpenMP

[krystophny]

Summary

• Wrap each target's compound pretty-mode status update in a named
  critical(fpm_progress) so it is atomic against other threads
• Make the n_complete counter coherent: !$omp atomic capture on increment
  and !$omp atomic read on use, replacing an unnamed critical write paired
  with an unsynchronized read
• Plain mode (off a TTY, including CI) is untouched: each line is a single
  self-contained write, so per-write atomicity already suffices

Context

Each target's pretty-mode update is a compound of two console_t writes, and
console_update_line moves the terminal cursor relative to the tracked line
count. On main the two writes sit in separate unnamed !$omp critical
regions, so another worker thread can interleave its own output between them,
change n_line, and invalidate the cursor arithmetic. The result is garbled
progress on an interactive terminal under -fopenmp.

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 --flag -fopenmp
[100%] Project compiled successfully.

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

The defect is a non-deterministic data race that only manifests in pretty/TTY
mode under multiple OpenMP threads, so there is no stable automated reproducer.
The before-state is visible in the source on main: the compound update spans
two separate unnamed critical regions in src/fpm_backend_output.f90, and
console_update_line in src/fpm_backend_console.f90 performs cursor movement
relative to a shared, concurrently-mutated n_line.