Merge dc/DC-084-arch-sami-caddy-healthcheck-removal: DC-084 remove redundant active Caddy health check from arch.sami [glm-grade=A]

The /etc/caddy/sites/arch.sami file had an active Caddy health check
(health_uri /api/stats health_interval 10s) probing the permanently
unreachable Arch Linux server (100.120.159.34:5000) every 10 seconds,
generating 6 syslog spam lines per minute with no dashboard value.

src/monitoring/caddy-upstream-watcher.js ALREADY provides equivalent
monitoring at 60s cadence with 5-min dead-confirmation, mute support,
incident creation, and dedup. The source comments explicitly call out
this exact spam as 'the noisy spam the dashboard currently sees for
100.120.159.34:5000'.

Live-verified on DNS2:
- caddy-apply validated + reloaded + committed
- Caddy admin API confirms health_uri/health_interval removed
- journal: 0 health_checker.active lines in last 5min (was ~30)
- container dashcaddy-api healthy (no restart needed)
- live HTTP all 200: status.sami, dashcaddy.net, ca.sami
- watcher correctly tracks 100.120.159.34:5000 as dead (1905+ failures)

Backup .bak-DC-084-pre deleted because Caddy's 'import sites/*' was
picking it up and causing 'ambiguous site definition' validation error.

GLM judge deleg_a87bc740 verdict: A — all live-verification claims
independently confirmed, fix is correct + minimal, no source code
changed, no container restart, no public-facing behavior change.

Co-Authored-By: Hermes <hermes@nousagent.com>

BACKLOG.md

@@ -400,3 +400,12 @@ Tickets DC-046 through DC-049 implement pluggable auth + email magic link. Sami
 - **prerequisite:** None.
 - **result:** Shipped codex-graded A. All 49 `console.*` sites in `src/managers/update-manager.js` now route through `log.info/log.warn/log.error` from `src/utils/logging` (tag = `'update'`). Mixed-content strings extracted into structured meta payloads (`containerName`, `schedule`, `imageName`, `error.message`, `digestPrefix`, `oldImageIdPrefix`, `httpStatus`, `maxAttempts`, `attempt`, `durationMs`, `scheduledTime`, etc.) so fields are queryable instead of inlined into the message. Errors now go through `log.error(ctx, errObj)` so they land in error.log with full stack trace + context, not just stderr. 1539/1539 Jest tests pass (78/78 update-manager tests still pass). ESLint: 14 pre-existing warnings in this file unchanged, zero new warnings introduced (verified with `git stash` baseline check).
 
+
+### DC-084: Remove redundant active Caddy health check from `arch.sami` site — eliminate 6 syslog spam lines/min
+- **status:** done
+- **owner:** hermes
+- **details:** `/etc/caddy/sites/arch.sami` had an active Caddy health check (`health_uri /api/stats health_interval 10s`) probing `100.120.159.34:5000` every 10 seconds. The upstream Arch Linux server `100.120.159.34` has been permanently unreachable (100% packet loss on ping, ports 5000 + 8080 both time out). Result: 6 `level:info HTTP request failed` journal lines per minute, 360/hour, 8640/day — pure noise, no dashboard value, no incident resolution. The `src/monitoring/caddy-upstream-watcher.js` (the same module whose source comments explicitly call out this exact spam as "the noisy spam the dashboard currently sees for `100.120.159.34:5000`") ALREADY provides equivalent monitoring: 60s probe cadence (6x less frequent), 5-minute confirmation window before opening incidents, mute toggle, deduped snapshot, incident integration with the health-checker. The active Caddy check is redundant. Fix: edit `/etc/caddy/sites/arch.sami` to remove the `health_uri / health_interval` block, leaving only `reverse_proxy 100.120.159.34:5000`. Apply via `caddy-apply` (validates+reloads+commits atomically). Backup `.bak-DC-084-pre` created pre-edit; deleted after `caddy-apply` succeeded because the `.bak` file was being picked up by Caddy's `import sites/*` and causing an "ambiguous site definition" validation error.
+- **impact:** Eliminates 100% of recurring caddy journal spam from the dead Arch upstream. The dashboard's `caddy-upstream-watcher.js` continues to monitor the dead upstream correctly (now at `consecutiveFailures: 1905+`, `lastSuccessAt: null`, `status: down`, `dead: true`) — operators see the dead upstream in the dashboard, just without the journal noise. Future Caddyfile authors who add an active health check to a `*.sami` site will be unaware that they should not (since the dashboard handles monitoring), so a follow-up could add a CLAUDE.md note or a Caddyfile lint warning. Out of scope for this tick.
+- **prerequisite:** None. `caddy-upstream-watcher.js` already provides equivalent monitoring.
+- **result:** Shipped GLM-pending (Codex quota dead). Before/after on DNS2 (`journalctl -u caddy --since "5 minutes ago" | grep health_checker.active | wc -l`): **before = ~30 entries / 5min** (active probe every 10s, all failing); **after = 0 entries / 5min**. Live-verified: `caddy validate` succeeded (after removing `.bak` file that caused `ambiguous site definition`), Caddy reloaded via `caddy-apply`, route `arch.sami → 100.120.159.34:5000` still active in admin API (verified via `curl http://localhost:2019/config/apps/http/servers/srv0/routes` — `health_uri: None, health_interval: None` confirms the block is gone). Container `dashcaddy-api Up About an hour (healthy)` (no restart needed — only Caddyfile changed, not container). Live HTTP smoke all green: `https://status.sami=200`, `https://dashcaddy.net=200`, `https://ca.sami=200`, `https://status.sami/api/health=401` (auth-gated, expected). Watcher state for `100.120.159.34:5000`: `consecutiveFailures: 1905`, `lastError: "probe timeout"`, `status: down`, `dead: true` — correctly tracked in `/opt/dashcaddy/dashcaddy-api/data/caddy-upstreams.json`. Backup deleted (would have caused site-definition ambiguity on next Caddy reload). Git: change lives only in DNS2's `/etc/caddy/sites/arch.sami` (the `/etc/caddy` git repo `.gitignore` excludes `sites/` per design — only the main `Caddyfile` is tracked). The dashcaddy source repo (`/root/dashcaddy`) carries only this BACKLOG.md documentation update on branch `dc/DC-084-arch-sami-caddy-healthcheck-removal`.
+- **Tests:** No source code change; existing `__tests__/caddy-upstream-watcher.test.js` 26/26 pass (baseline preserved). 2465/2465 repo tests pass (4 pre-existing billing test suites fail with `Cannot find module pdfkit` — unrelated to this change).