feat(builtins): add --help and --version support to all tools

[chaliy]

Summary

• Add check_help_version() helper in builtins/mod.rs that handles --help and --version long flags (short flags -h/-V excluded since they have different meanings in many tools like sort -V, ls -h, grep -h)
• Add --help and --version support to ~80 builtin commands across all categories: text processing, file operations, path/system, data/archive, and pipeline tools
• Special handling for jq (supports -h/-V directly since those are genuine help/version flags for jq)
• Update specs/005-builtins.md documenting the standard flags convention

Test plan

• Unit tests for check_help_version helper (5 cases: help, version, no version configured, stops at non-flag, no match)
• Integration spec tests verifying --help/--version for representative tools (cat, grep, sort, ls, date)
• Tests marked bash_diff since help output intentionally differs from real bash
• All 2371 unit tests pass
• All 15 spec test suites pass (1974 bash specs, 99.9% pass rate)
• cargo fmt --check clean
• cargo clippy --all-targets --all-features -- -D warnings clean
• Rebased on latest main