feat(audit): comprehensive logging — auth events, severity, source, IP

Audit log was previously silent on authentication and on background
work. This wires:

- Login (success + failed) and logout via a wrapper around better-auth's
  [...all] handler. Failed logins are severity 'warning' and carry the
  attempted email so brute-force attempts surface in the inspector.
- New severity (info|warning|error|critical) and source (user|auth|
  system|webhook|cron|job) columns on audit_logs. permission_denied
  defaults to 'warning', hard_delete to 'critical'.
- Webhook delivery success/failure/DLQ/retry now write audit rows
  alongside the webhook_deliveries detail table.
- IP address is now visible as a column in the inspector (was already
  captured at the helper level).
- Audit UI: severity badges per row, severity + source dropdowns, IP
  column, expanded action filter covering hard-delete, webhook events,
  job/cron events.

Migration 0044 adds the two columns + their port-scoped indexes.
1175/1175 vitest passing.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/lib/audit.ts

@@ -25,7 +25,14 @@ export type AuditAction =
   | 'send'
   | 'view'
   | 'request_hard_delete_code'
-  | 'hard_delete';
+  | 'hard_delete'
+  // System / background events.
+  | 'webhook_delivered'
+  | 'webhook_failed'
+  | 'webhook_dead_letter'
+  | 'webhook_retried'
+  | 'job_failed'
+  | 'cron_run';
 
 /**
  * Common shape passed to service functions so they can stamp audit logs and
@@ -40,6 +47,9 @@ export interface AuditMeta {
   userAgent: string;
 }
 
+export type AuditSeverity = 'info' | 'warning' | 'error' | 'critical';
+export type AuditSource = 'user' | 'system' | 'auth' | 'webhook' | 'cron' | 'job';
+
 export interface AuditLogParams {
   /** Null for system-generated events. */
   userId: string | null;
@@ -56,6 +66,14 @@ export interface AuditLogParams {
    *  jobs, internal helpers) may omit. */
   ipAddress?: string;
   userAgent?: string;
+  /** Defaults to 'info'. Bump to 'warning' for permission_denied,
+   *  'error' for failed background jobs / webhook DLQ, 'critical' for
+   *  hard-deletes / security-relevant events. */
+  severity?: AuditSeverity;
+  /** Defaults to 'user'. Use 'auth' for session lifecycle,
+   *  'webhook' for delivery events, 'job' / 'cron' / 'system' for
+   *  background work. The inspector filters on this column. */
+  source?: AuditSource;
 }
 
 const SENSITIVE_FIELDS = new Set(['email', 'phone', 'password', 'credentials_enc', 'token']);
@@ -103,8 +121,19 @@ export function diffFields(
  * This function NEVER throws - errors are caught and logged so that an audit
  * failure never rolls back or disrupts the parent operation.
  */
+// Some actions get a default severity bump so callers don't have to
+// remember; explicit `severity` on the call still wins.
+const DEFAULT_SEVERITY_BY_ACTION: Partial<Record<AuditAction, AuditSeverity>> = {
+  permission_denied: 'warning',
+  hard_delete: 'critical',
+};
+const AUTH_ACTIONS = new Set<AuditAction>(['login', 'logout', 'password_change']);
+
 export async function createAuditLog(params: AuditLogParams): Promise<void> {
   try {
+    const severity = params.severity ?? DEFAULT_SEVERITY_BY_ACTION[params.action] ?? 'info';
+    const source = params.source ?? (AUTH_ACTIONS.has(params.action) ? 'auth' : 'user');
+
     await db.insert(auditLogs).values({
       portId: params.portId,
       userId: params.userId,
@@ -117,6 +146,8 @@ export async function createAuditLog(params: AuditLogParams): Promise<void> {
       metadata: params.metadata ?? null,
       ipAddress: params.ipAddress ?? null,
       userAgent: params.userAgent ?? null,
+      severity,
+      source,
     });
   } catch (err) {
     // Strip old/new values from the log to avoid secondary exposure of the data