Add report list and extend report divergence with --env/--height

[bdchatham]

Summary

• Adds seictl report list to inventory shadow comparison data in S3
• Extends seictl report divergence with --env/--height convenience flags
• Both commands support --json for agent consumption

What this does

report list --env prod — shows what comparison pages and divergence reports exist:

3 comparison page(s), 1 divergence report(s), 300 blocks covered

TYPE         HEIGHT RANGE              BLOCKS
page         198000000 - 198000099     100
page         198000100 - 198000199     100
page         198000200 - 198000242     43
divergence   198000242                 -

report divergence --env prod --height 198000242 — fetches the divergence report without needing to know the S3 key. Equivalent to --bucket prod-sei-shadow-results --key shadow-results/divergence-198000242.report.json.gz.

Why this scope

The shadow replayer crashes on app hash divergence, producing a handful of matching pages + exactly 1 divergence report. The investigation workflow is: "did it diverge?" → "show me the report." These two commands serve that workflow. Statistical analysis (summary, search, trends) was evaluated and cut per YAGNI — the data shape doesn't support it.

Changes

• report.go — extended divergence command, resolveS3Ref() helper, registered list
• report_list.go — new report list command with S3 listing + key parsing
• sidecar/shadow/fetch.go — extracted FetchReport() for testability
• sidecar/s3/client.go — new Downloader interface for streaming S3 reads

No new dependencies. No sidecar/task engine/OpenAPI changes.

Test plan

• seictl report list --env prod returns inventory
• seictl report list --env prod --json returns structured JSON
• seictl report divergence --env prod --height N fetches and renders report
• seictl report divergence --env prod --height N --json returns raw JSON
• --key and --height are mutually exclusive (error)
• --env and --bucket are mutually exclusive (error)

🤖 Generated with Claude Code

[bdchatham]

LGTM