Implement dashboard and audit log templates, add paginated audit log support

- Added `web/templates/{dashboard,audit,base,accounts,account_detail}.html` for a consistent UI.
- Implemented new audit log endpoint (`GET /v1/audit`) with filtering and pagination via `ListAuditEventsPaged`.
- Extended `AuditQueryParams`, added `AuditEventView` for joined actor/target usernames.
- Updated configuration (`goimports` preference), linting rules, and E2E tests.
- No logic changes to existing APIs.

web/templates/audit.html

@@ -0,0 +1,43 @@
+{{define "audit"}}{{template "base" .}}{{end}}
+{{define "title"}}Audit Log — MCIAS{{end}}
+{{define "content"}}
+<div class="page-header d-flex align-center justify-between">
+  <div>
+    <h1>Audit Log</h1>
+    <p class="text-muted text-small">{{.Total}} total events</p>
+  </div>
+  <form class="d-flex gap-1 align-center" style="font-size:.9rem">
+    <select class="form-control" name="event_type" style="width:auto"
+            hx-get="/audit/rows" hx-target="#audit-tbody" hx-swap="innerHTML"
+            hx-trigger="change">
+      <option value="">All events</option>
+      {{range .EventTypes}}<option value="{{.}}"{{if eq $.FilterType .}} selected{{end}}>{{.}}</option>{{end}}
+    </select>
+  </form>
+</div>
+<div class="table-wrapper">
+  <table>
+    <thead>
+      <tr><th>Time</th><th>Event</th><th>Actor</th><th>Target</th><th>IP</th><th>Details</th></tr>
+    </thead>
+    <tbody id="audit-tbody">
+      {{template "audit_rows" .}}
+    </tbody>
+  </table>
+</div>
+{{if gt .TotalPages 1}}
+<div class="d-flex gap-1 align-center mt-2" style="font-size:.9rem;color:#64748b">
+  <span>Page {{.Page}} of {{.TotalPages}}</span>
+  {{if gt .Page 1}}
+  <button class="btn btn-sm btn-secondary"
+          hx-get="/audit/rows?page={{sub .Page 1}}&event_type={{.FilterType}}"
+          hx-target="#audit-tbody" hx-swap="innerHTML">← Prev</button>
+  {{end}}
+  {{if lt .Page .TotalPages}}
+  <button class="btn btn-sm btn-secondary"
+          hx-get="/audit/rows?page={{add .Page 1}}&event_type={{.FilterType}}"
+          hx-target="#audit-tbody" hx-swap="innerHTML">Next →</button>
+  {{end}}
+</div>
+{{end}}
+{{end}}