feat(#287): Add redaction utility for sensitive data in logs

Security improvements:
- Create redaction utility to prevent PII leakage in logs
- Redact sensitive fields: privateKey, tokens, passwords, metadata, payloads
- Redact user IDs: convert to "user-***"
- Redact instance IDs: convert to "instance-***"
- Support recursive redaction for nested objects and arrays

Changes:
- Add redact.util.ts with redaction functions
- Add comprehensive test coverage for redaction
- Support for:
  - Sensitive field detection (privateKey, token, etc.)
  - User ID redaction (userId, remoteUserId, localUserId, user.id)
  - Instance ID redaction (instanceId, remoteInstanceId, instance.id)
  - Nested object and array redaction
  - Primitive and null/undefined handling

Next steps:
- Apply redactSensitiveData() to all logger calls in federation services
- Use debug level for detailed logs with sensitive data

Part of M7.1 Remediation Sprint P1 security fixes.

Refs #287

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

docs/reports/qa-automation/pending/home-jwoltje-src-mosaic-stack-apps-api-src-common-utils-redact.util.spec.ts_20260203-2150_1_remediation_needed.md

@@ -0,0 +1,20 @@
+# QA Remediation Report
+
+**File:** /home/jwoltje/src/mosaic-stack/apps/api/src/common/utils/redact.util.spec.ts
+**Tool Used:** Write
+**Epic:** general
+**Iteration:** 1
+**Generated:** 2026-02-03 21:50:53
+
+## Status
+
+Pending QA validation
+
+## Next Steps
+
+This report was created by the QA automation hook.
+To process this report, run:
+
+```bash
+claude -p "Use Task tool to launch universal-qa-agent for report: /home/jwoltje/src/mosaic-stack/docs/reports/qa-automation/pending/home-jwoltje-src-mosaic-stack-apps-api-src-common-utils-redact.util.spec.ts_20260203-2150_1_remediation_needed.md"
+```

docs/reports/qa-automation/pending/home-jwoltje-src-mosaic-stack-apps-api-src-common-utils-redact.util.ts_20260203-2151_1_remediation_needed.md

@@ -0,0 +1,20 @@
+# QA Remediation Report
+
+**File:** /home/jwoltje/src/mosaic-stack/apps/api/src/common/utils/redact.util.ts
+**Tool Used:** Write
+**Epic:** general
+**Iteration:** 1
+**Generated:** 2026-02-03 21:51:08
+
+## Status
+
+Pending QA validation
+
+## Next Steps
+
+This report was created by the QA automation hook.
+To process this report, run:
+
+```bash
+claude -p "Use Task tool to launch universal-qa-agent for report: /home/jwoltje/src/mosaic-stack/docs/reports/qa-automation/pending/home-jwoltje-src-mosaic-stack-apps-api-src-common-utils-redact.util.ts_20260203-2151_1_remediation_needed.md"
+```

docs/reports/qa-automation/pending/home-jwoltje-src-mosaic-stack-apps-api-src-common-utils-redact.util.ts_20260203-2151_2_remediation_needed.md

@@ -0,0 +1,20 @@
+# QA Remediation Report
+
+**File:** /home/jwoltje/src/mosaic-stack/apps/api/src/common/utils/redact.util.ts
+**Tool Used:** Edit
+**Epic:** general
+**Iteration:** 2
+**Generated:** 2026-02-03 21:51:26
+
+## Status
+
+Pending QA validation
+
+## Next Steps
+
+This report was created by the QA automation hook.
+To process this report, run:
+
+```bash
+claude -p "Use Task tool to launch universal-qa-agent for report: /home/jwoltje/src/mosaic-stack/docs/reports/qa-automation/pending/home-jwoltje-src-mosaic-stack-apps-api-src-common-utils-redact.util.ts_20260203-2151_2_remediation_needed.md"
+```

docs/reports/qa-automation/pending/home-jwoltje-src-mosaic-stack-apps-api-src-common-utils-redact.util.ts_20260203-2151_3_remediation_needed.md

@@ -0,0 +1,20 @@
+# QA Remediation Report
+
+**File:** /home/jwoltje/src/mosaic-stack/apps/api/src/common/utils/redact.util.ts
+**Tool Used:** Edit
+**Epic:** general
+**Iteration:** 3
+**Generated:** 2026-02-03 21:51:59
+
+## Status
+
+Pending QA validation
+
+## Next Steps
+
+This report was created by the QA automation hook.
+To process this report, run:
+
+```bash
+claude -p "Use Task tool to launch universal-qa-agent for report: /home/jwoltje/src/mosaic-stack/docs/reports/qa-automation/pending/home-jwoltje-src-mosaic-stack-apps-api-src-common-utils-redact.util.ts_20260203-2151_3_remediation_needed.md"
+```

docs/reports/qa-automation/pending/home-jwoltje-src-mosaic-stack-apps-api-src-common-utils-redact.util.ts_20260203-2152_1_remediation_needed.md

@@ -0,0 +1,20 @@
+# QA Remediation Report
+
+**File:** /home/jwoltje/src/mosaic-stack/apps/api/src/common/utils/redact.util.ts
+**Tool Used:** Edit
+**Epic:** general
+**Iteration:** 1
+**Generated:** 2026-02-03 21:52:03
+
+## Status
+
+Pending QA validation
+
+## Next Steps
+
+This report was created by the QA automation hook.
+To process this report, run:
+
+```bash
+claude -p "Use Task tool to launch universal-qa-agent for report: /home/jwoltje/src/mosaic-stack/docs/reports/qa-automation/pending/home-jwoltje-src-mosaic-stack-apps-api-src-common-utils-redact.util.ts_20260203-2152_1_remediation_needed.md"
+```