security(logging): normalize and redact server-side and worker errors #687

Parent epic: #679
Related completed foundations: #403, #447

Evidence

The structured logger and audit foundation exists, but multiple admin Astro pages and scripts still use raw console.error(..., error) or surface error.message. This is a narrow remediation issue, not a replacement for #403/#447.

Objective

Route server-side, API, and worker failures through the safe structured logger and standard error taxonomy.

Scope

• Inventory raw exception logging in src/pages/admin, API handlers, and scripts/.
• Replace unsafe console calls with correlation-aware structured events.
• Normalize public/operator error codes; retain detailed cause only in appropriately protected diagnostics.
• Extend redaction for credentials, tokens, cookies, authorization headers, DSNs, email/IP where applicable.
• Add a lint/static check for prohibited server-side patterns.

Acceptance criteria

• No raw Error object or request secret is emitted by covered runtime paths.
• Client responses remain safe and stable.
• Tests exercise nested causes and representative secret formats.
• Worker CLI JSON output separates safe diagnostics from exit codes.
• Logging/threat-model docs describe operator-safe troubleshooting.