feat(telemetry): capture error_class on setup_complete failures

[George-iam]

Summary

When setup fails, the dashboard's Phase Failures view (/admin/analytics → Code → Setup health) showed only the failed phase — auth_check: 7, init_scan: 1 — but error_class was always NULL, so it was impossible to tell why setup failed without grepping logs.

This PR populates error_class on the setup_complete event:

Phase	error_class set to	Why
auth_check	"oauth_missing"	No Claude subscription and no ANTHROPIC_API_KEY env var — caller never authenticated. Slug already exists in the bounded ErrorClass vocab.
init_scan	classifyError(err)	Same classification we already feed into the separate error event; now also stamped onto setup_complete so it's visible in one row of the dashboard's Phase Failures table.

Backend ingestion already reads error_class from any event payload (misc_routes.py:2100) — no migration, no schema change.

Why now

Dashboard at https://cloud.axme.ai/admin/analytics currently shows:

• auth_check: 7 — looking at raw rows, these are all real users who ran axme-code setup without authenticating. Not a bug — but with this fix the dashboard will show auth_check / oauth_missing: 7 so an operator can read it without DB access.
• init_scan: 1 — one user's LLM scan threw; error_class was NULL so I couldn't tell from the dashboard whether it was timeout, api_error, api_rate_limit, etc. With this fix the next such failure will be self-describing.

Files changed

src/cli.ts — 5 lines:

• Add setupErrorClass: ErrorClass | null next to existing setupPhaseFailed.
• Set on auth_check and init_scan branches.
• Include error_class in the sendTelemetryBlocking("setup_complete", { ... }) payload.

Test plan

• Type-check clean (npx tsc --noEmit)
• Full unit test suite passes (608/608)
• Bundle builds (npm run build)
• After next release: verify error_class populated for any new setup-failed rows on the dashboard

After merge

Effective for users on the next CLI release. Existing rows in telemetry_events are unchanged — the historical 7 + 1 stay NULL.

🤖 Generated with Claude Code