feat: comprehensive security, performance, UX and deployment audit

Security:
- CORS restricted to explicit methods/headers, configurable via CORS_ORIGINS env
- Auth added to /reports/{rid}/html and /compliance-report endpoints
- Ownership check on report downloads
- Rate limiting on login (10 attempts/5min per IP with threading.Lock)
- Non-root container user (agent via gosu entrypoint)
- Nginx security headers (X-Frame-Options, X-Content-Type-Options, X-XSS-Protection, Referrer-Policy, Permissions-Policy)
- .gitignore and .dockerignore for secret leak prevention
- .env.example with documentation

Performance:
- 16 SQLite indexes on foreign keys and frequently queried columns
- Pagination on chat messages (100), reports (50), audit log (100)
- subprocess.run wrapped in run_in_executor (3 async handlers)
- asyncio.wait_for timeouts on GenAI calls (300s) and Chromium PDF (120s)
- Thread pool reduced to 10 workers
- Code splitting with React.lazy (bundle: 1.3MB -> ~550KB initial)
- React.memo on TreeItem (recursive compartment tree)

Error handling:
- 13 bare except clauses replaced with logged Exception handlers
- Graceful shutdown handler (terminates subprocesses + executor)
- File upload validation (50MB max, extension whitelist per endpoint)
- Health check expanded (version, uptime, db_ok)
- Cache-Control on /api/genai/models (1h)
- Auto-cleanup audit_log > 30 days

Dead code removed:
- DownloadsPage.tsx, StubPage.tsx, MfaPage.tsx (moved to UsersPage)
- Legacy frontend/ directory
- 19 unused i18n keys, dist/ removed from git tracking

UX & i18n:
- 8 alert() calls replaced with styled error states (TerraformPage)
- 50+ hardcoded Portuguese strings localized to i18n (pt/en) across 11 files
- aria-label on all icon-only buttons (Chat, Explorer, Sidebar)
- focus-visible CSS for keyboard navigation
- Responsive grid fix (360px -> 280px for mobile)
- aria-hidden on decorative SVGs

Deployment:
- Docker resource limits (backend 4G, frontend 512M)
- Log rotation (json-file, 10MB x 3)
- Terraform version parameterized via ARG

frontend-react/src/pages/config/McpServersPage.tsx

@@ -133,28 +133,28 @@ export default function McpServersPage() {
       } else {
         await mcpApi.create(body);
       }
-      setFormMsg({ type: 's', text: `Server ${editing ? 'atualizado' : 'registrado'} com sucesso!` });
+      setFormMsg({ type: 's', text: editing ? t('mcp.updatedSuccess') : t('mcp.savedSuccess') });
       await fetchServers();
       useAppStore.getState().loadData();
       setTimeout(resetForm, 1200);
     } catch (err) {
-      setFormMsg({ type: 'e', text: err instanceof Error ? err.message : 'Erro ao salvar' });
+      setFormMsg({ type: 'e', text: err instanceof Error ? err.message : t('common.errorSave') });
       setSaving(false);
     }
   };
 
   const handleDelete = async (id: string) => {
     setConfirmDelete(null);
-    setTableMsg({ type: 'i', text: 'Excluindo server...' });
+    setTableMsg({ type: 'i', text: t('mcp.deletingServer') });
     try {
       await mcpApi.remove(id);
       await fetchServers();
       useAppStore.getState().loadData();
-      setTableMsg({ type: 's', text: 'Server excluido com sucesso!' });
+      setTableMsg({ type: 's', text: t('mcp.deletedSuccess') });
       if (editing?.id === id) resetForm();
       setTimeout(() => setTableMsg(null), 3000);
     } catch (err) {
-      setTableMsg({ type: 'e', text: err instanceof Error ? err.message : 'Erro ao excluir' });
+      setTableMsg({ type: 'e', text: err instanceof Error ? err.message : t('common.errorDelete') });
     }
   };
 
@@ -178,11 +178,11 @@ export default function McpServersPage() {
       const res = await mcpApi.discoverTools(id);
       await fetchServers();
       useAppStore.getState().loadData();
-      setTableMsg({ type: 's', text: `${res.discovered} tool(s) descoberta(s), ${res.total} total` });
+      setTableMsg({ type: 's', text: t('mcp.discoveredTools').replace('{0}', String(res.discovered)).replace('{1}', String(res.total)) });
       setExpandedTools((p) => ({ ...p, [id]: true }));
       setTimeout(() => setTableMsg(null), 4000);
     } catch (err) {
-      setTableMsg({ type: 'e', text: err instanceof Error ? err.message : 'Erro ao descobrir tools' });
+      setTableMsg({ type: 'e', text: err instanceof Error ? err.message : t('mcp.errorDiscoverTools') });
     } finally {
       setDiscovering((p) => ({ ...p, [id]: false }));
     }
@@ -193,7 +193,7 @@ export default function McpServersPage() {
     if (!srv?.tools) return;
     const tool = srv.tools[idx];
     const toolName = typeof tool === 'string' ? tool : (tool as McpToolDef).name;
-    if (!confirm(`Remover tool "${toolName}"?`)) return;
+    if (!confirm(t('mcp.removeToolConfirm').replace('{0}', toolName))) return;
     const newTools = [...srv.tools];
     newTools.splice(idx, 1);
     try {
@@ -422,7 +422,7 @@ export default function McpServersPage() {
             <div className="px-5 pb-5 flex flex-col gap-4" style={{ borderTop: '1px solid var(--bd)' }}>
               <p className="text-[.7rem] pt-3" style={{ color: 'var(--t4)' }}>
                 {editing
-                  ? <>Editando: <strong style={{ color: 'var(--t2)' }}>{editing.name}</strong></>
+                  ? <>{t('mcp.editingLabel')} <strong style={{ color: 'var(--t2)' }}>{editing.name}</strong></>
                   : t('mcp.configDesc')}
               </p>