Implement and schedule Daily Support Checks #784

Summary

Implement and document the Daily Support Checks scheduled task and reporting workflow.

What was added

• A PowerShell-based Daily Support Check runner under ScheduledTasks/DailySupportCheck.
• Configurable checks for:
  • PowerShell runtime availability
  • Report output directory
  • Disk space
  • Health Monitoring services
  • Subscription service status
  • KurrentDB projections
  • Scheduled tasks
  • KurrentDB write activity
  • Template/configuration validation
• Configuration-driven enablement and settings through daily-support-check.json.
• Environment-variable-based secret handling for KurrentDB and Brevo credentials; secrets are not stored in the JSON configuration.

Reporting

• JSON reports retain detailed check results and diagnostics.
• HTML reports use a compact three-column layout: check name, traffic-light status icon, and short summary.
• Failure summaries are kept short while full details remain available in JSON.
• Email subjects include overall status, server name, and report date:
  Daily Support Check - <Status> - <ServerName> - <YYYY-MM-DD>
• Brevo API is used for email delivery.
• Report retention is configurable through ReportRetentionDays, with a default of 7 days.

Scheduling and CI/CD

• Added DailySupportCheck.xml for Windows Task Scheduler.
• The task runs daily at 09:00 using PowerShell 7 and the configured report output path.
• Pull request workflow runs the Daily Support Check Pester tests.
• Push-to-main and release workflows package the scheduled task, script, and base configuration.
• Machine-local secrets and overrides remain outside the repository configuration.

Fixes included

• Corrected handling of the subscription-service response so all subscriptions are evaluated rather than treating the response as a single subscription object.
• Replaced the flagged ConvertTo-SecureString -AsPlainText call with a read-only SecureString built directly for the PSCredential boundary.
• Added a focused test proving the secure-string conversion remains read-only and round-trips correctly for authentication use.

Verification

• Local Daily Support Check Pester suite: 35 passed, 0 failed.
• Focused secure-string helper validation passed.
• CodeQL and repository workflow checks passed on PR feat: add daily support check reporting #783.
• PR: feat: add daily support check reporting #783
• Implementation commit: d7d33c2

Known follow-up

Codacy still reports a security annotation related to the previous plaintext conversion pattern, despite the call being removed from the implementation. The remaining Codacy result should be reviewed as a stale or mislocated analyzer finding and cleared or documented in Codacy as appropriate.

Acceptance criteria

• Daily checks can be run manually and from Windows Task Scheduler.
• Reports are generated in JSON and compact HTML formats.
• Brevo email delivery works using environment-provided credentials.
• Reports older than the configured retention period are removed.
• Pull request and release workflows include the required script, configuration, tests, and schedule definition.
• All automated checks pass, including resolution of the remaining Codacy finding.