Add aura verify chain command

[DebayanSen96]

Description

Adds aura verify chain <path> to validate an exported JSONL audit hash chain for CI and compliance archives. Valid chains print {"hash_chain_valid": true}; broken chains print the first affected event_id and exit with status 1.

Type

• Bug fix
• Core framework — session, spine, constraints, identity, audit report
• CLI
• Integration — sequencer, hosts, membrane, observers, exporters
• Documentation
• Examples
• Packaging / CI

Checklist

• Linked issue (Refs [CLI]: aura verify chain — validate hash chain on archived session JSONL #24)
• pytest passes
• black aura tests — no diff
• flake8 aura tests — clean
• CHANGELOG.md updated when user-visible behavior changes

Test plan

• pytest -q — 64 passed, 1 skipped
• black --check aura tests
• flake8 aura tests
• python3 -m compileall -q aura tests

Closes #24

[rosspeili]

Thanks and welcome @DebayanSen96, this LGTM.

Before or right after merge, two small follow-ups would save a second PR:

1. Add aura verify chain <path> to the Sessions group in aura/cli/help_text.py (grouped aura --help / interactive menu).
2. Optional: extract the “first broken event_id” walk into aura/core/spine.py next to verify_hash_chain() so we don’t duplicate chain logic in the CLI.

We’ll merge with Closes #24 or you can add closes or fixes 24 to your pr description. Appreciate the contribution, welcome to the harness. <3

[DebayanSen96]

Thanks @rosspeili — both follow-ups are included in 196cb7d: aura verify chain <path> is now listed in the Sessions help and interactive menu, and the first broken event_id walk is shared from aura/core/spine.py. I also updated the description with Closes #24. Verified with 64 passed, 1 skipped, plus Black, Flake8, and compileall.

[rosspeili]

Thanks again @DebayanSen96, LGTM, will merge after green ci, closes #24.

Nits if you wanna tighten this up with follow up:

• Broken chains walk the spine twice, fine for now.
• Empty/no-hash JSONL reports invalid without event_id, edge case only.
• Missing-file path untested, trivial if you ever touch this again.