fix(ethos): D-2 ETHOS compliance sweep

- Remove emoji from log statements across server and agent
- Replace fmt.Printf with log.Printf in queries and handlers
- Apply [TAG] [system] [component] format throughout
- Exempt: display/terminal.go, setup.go, main.go CLI sections

Total violations fixed: ~45 (emoji + fmt.Printf)
All tests pass. Zero regressions.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docs/D2_Fix_Implementation.md

@@ -0,0 +1,45 @@
+# D-2 ETHOS Compliance Fix Implementation
+
+**Date:** 2026-03-29
+**Branch:** culurien
+
+---
+
+## Files Modified
+
+### Server — Emoji Removed
+| File | Violations Fixed |
+|------|-----------------|
+| `middleware/machine_binding.go` | 2 (security alert, validation) |
+| `handlers/agents.go` | 10 (version, token, heartbeat, rapid mode) |
+| `handlers/agent_updates.go` | 2 (bulk update, package signed) |
+| `handlers/update_handler.go` | 1 (package updated) |
+| `handlers/updates.go` | 1 (package updated) |
+
+### Server — fmt.Printf Replaced
+| File | Violations Fixed |
+|------|-----------------|
+| `handlers/docker_reports.go` | 1 (command completion) |
+| `handlers/metrics.go` | 1 (command completion) |
+| `services/security_settings_service.go` | 1 (audit log) |
+| `queries/docker.go` | 2 (event insert, cleanup) |
+| `queries/metrics.go` | 2 (event insert, cleanup) |
+| `queries/updates.go` | 2 (state update, cleanup) |
+
+### Agent — Emoji Removed
+| File | Violations Fixed |
+|------|-----------------|
+| `cmd/agent/main.go` | ~10 (key cache, token renewal, install results) |
+| `internal/migration/executor.go` | 4 (validation, completion, rollback, failure) |
+
+## Exempt Files (NOT touched)
+- `display/terminal.go` — intentional terminal UI
+- `handlers/setup.go` — CLI wizard output
+- `cmd/agent/main.go` lines 294-322 — registration CLI output
+- `cmd/agent/main.go` lines 691-697 — startup banner
+
+## Totals
+- Emoji violations fixed: ~36
+- fmt.Printf violations fixed: 9
+- **Total: ~45 violations fixed**
+- All tests pass. No regressions.