feat(scripts): --help/--version on cap-probe, score-checkpoint, force-claim

[NagyVikt]

Summary

Implements docs/future/PROTOCOL.md §22.4.1 (PROPOSED → done): wires
--help / -h and --version flags into three previously flag-less
bash entry points via a tiny shared lib.

• scripts/codex-fleet/lib/version.sh — new. Exposes FLEET_VERSION
  (env override > nearest git tag > 0.0.0-dev) and
  handle_help_version_flags "$@".
• scripts/codex-fleet/{cap-probe,score-checkpoint,force-claim}.sh —
  each sources lib/version.sh and calls handle_help_version_flags
  before its real argv parsing. Every existing flag / arg still passes
  through unchanged.
• tests/scripts/test-script-help.sh — new smoke test asserting exit 0
  • non-empty, script-name-bearing stdout for all six --help /
    --version invocations.

No existing logic was refactored; this is purely additive.

Acceptance evidence

$ bash scripts/codex-fleet/cap-probe.sh --help          # exit=0
cap-probe.sh — verify candidate codex accounts are usable.
$ bash scripts/codex-fleet/cap-probe.sh --version       # exit=0
cap-probe.sh 0.0.0-dev
$ bash scripts/codex-fleet/score-checkpoint.sh --help   # exit=0
score-checkpoint.sh — score uncommitted diffs in active Guardex
$ bash scripts/codex-fleet/score-checkpoint.sh --version # exit=0
score-checkpoint.sh 0.0.0-dev
$ bash scripts/codex-fleet/force-claim.sh --help        # exit=0
force-claim.sh — dispatch ready plan sub-tasks across all
$ bash scripts/codex-fleet/force-claim.sh --version     # exit=0
force-claim.sh 0.0.0-dev
$ bash tests/scripts/test-script-help.sh
test-script-help: 6 passed, 0 failed                    # exit=0
$ bash -n on all five touched files                     # OK

shellcheck was unavailable on the build host; bash -n parsed every
modified file cleanly. Pass-through sanity check:
bash scripts/codex-fleet/force-claim.sh --dry-run still runs one_pass
and exits 0.

Test plan

• --help exits 0 with non-empty stdout for all three scripts
• --version exits 0 and prints <basename> <version> for all three
• tests/scripts/test-script-help.sh exits 0
• bash -n on every touched file
• CI green