Document session close and audit exports

[DebayanSen96]

Summary: Refreshes docs/using-aura.md with current audit-only and prescriptive postures, session-close artifacts, AuditReport fields, and the report/export/verify CLI workflow. Also documents approver principals, OTel refresh behavior, and the related output/getting-started references. Closes #37. Checklist: linked issue; pytest passes; black aura tests clean; flake8 aura tests clean. Test plan: pytest -q (74 passed, 8 skipped); black --check aura tests; flake8 aura tests; python3 -m compileall -q aura tests; git diff --check.

[rosspeili]

Thanks @DebayanSen96, this looks good too.

You would probably have to rebase onto main after #44 merges, as this PR documents aura report show, which only exists in #44.

Please add in this PR before merge (explicit #37 acceptance, do not defer):

• docs/using-aura.md, SDK table, change run.approve(request_id) to document principal= (e.g. run.approve(request_id, principal="operator@corp")) and one line in Session close and export: principal is recorded on gated calls and appears in export / OTel (aura.principal).
• CHANGELOG.md, [Unreleased] entry: using-aura session close, audit report, export CLI workflow ([Docs]: using-aura.md — session close, audit report, and export CLI #37).
• docs/outputs.md, if Add aura report show CLI command #44 doesn’t land first, add aura report show here too; if Add aura report show CLI command #44 lands first, add cross-link from Audit report section → using-aura.
• docs/getting-started.md, add aura report show to CLI block (same as Add aura report show CLI command #44 ripple, include here so [Docs]: using-aura.md — session close, audit report, and export CLI #37 doc pass is complete even if PRs merge out of order).
• OTel accuracy, {session_id}.otel.jsonl is written on session close by default (include_otel=True); clarify that aura export-otel regenerates/refreshes it (table currently says “Optional” which reads as manual-only).
• PR description, Closes #37 (not Refs).

Finaly, same as 44, please comment on #37 to get assigned the issue, and please claim issues (or create issues), get assigned to them, before opening PRs in the future <3 appreciate it.

[rosspeili]

Thanks @DebayanSen96, this closes #37. I just rebased onto main after #44, resolved CHANGELOG/outputs conflicts (kept both #25 and #37 entries). One tiny maintainer tweak: aligned the OTel artifact row in using-aura.md with outputs.md. LGTM, merging. <3

[DebayanSen96]

Thanks @rosspeili. Appreciate the review and the cleanup on the OTel row.