feat: add ideation feature with per-tenant toggle

Adds idea submission capability gated by a per-tenant feature flag.
Super admins can enable/disable ideation for specific tenants via the
admin tenant detail drawer. Users see a lightbulb icon in the header
when enabled, opening a modal to submit ideas (title + description).
Ideas are stored in shared schema for cross-tenant backlog querying.

- Database: shared.ideas table (018-ideas.sql migration)
- Backend: Ideas NestJS module (entity, service, controller)
- Admin API: GET /admin/ideas, PUT /admin/ideas/:id/status,
  PUT /admin/organizations/:id/settings
- Frontend: IdeaModal component, lightbulb ActionIcon in header
- Admin UI: Feature Toggles card with ideation Switch in drawer

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/components/ideas/IdeaModal.tsx

@@ -0,0 +1,69 @@
+import { useState } from 'react';
+import { Modal, TextInput, Textarea, Button, Stack } from '@mantine/core';
+import { notifications } from '@mantine/notifications';
+import { useMutation } from '@tanstack/react-query';
+import api from '../../services/api';
+
+interface IdeaModalProps {
+  opened: boolean;
+  onClose: () => void;
+}
+
+export function IdeaModal({ opened, onClose }: IdeaModalProps) {
+  const [title, setTitle] = useState('');
+  const [description, setDescription] = useState('');
+
+  const submitIdea = useMutation({
+    mutationFn: async () => {
+      const { data } = await api.post('/ideas', { title, description });
+      return data;
+    },
+    onSuccess: () => {
+      notifications.show({ message: 'Idea submitted — thank you!', color: 'green' });
+      setTitle('');
+      setDescription('');
+      onClose();
+    },
+    onError: (err: any) => {
+      notifications.show({
+        message: err.response?.data?.message || 'Failed to submit idea',
+        color: 'red',
+      });
+    },
+  });
+
+  const handleClose = () => {
+    setTitle('');
+    setDescription('');
+    onClose();
+  };
+
+  return (
+    <Modal opened={opened} onClose={handleClose} title="Submit an Idea" size="md">
+      <Stack>
+        <TextInput
+          label="Title"
+          placeholder="Brief summary of your idea"
+          required
+          value={title}
+          onChange={(e) => setTitle(e.currentTarget.value)}
+          maxLength={255}
+        />
+        <Textarea
+          label="Description"
+          placeholder="Describe your idea in more detail (optional)"
+          minRows={4}
+          value={description}
+          onChange={(e) => setDescription(e.currentTarget.value)}
+        />
+        <Button
+          onClick={() => submitIdea.mutate()}
+          loading={submitIdea.isPending}
+          disabled={!title.trim()}
+        >
+          Submit Idea
+        </Button>
+      </Stack>
+    </Modal>
+  );
+}

frontend/src/components/layout/AppLayout.tsx

@@ -11,6 +11,7 @@ import {
   IconEyeOff,
   IconSun,
   IconMoon,
+  IconBulb,
 } from '@tabler/icons-react';
 import { Outlet, useNavigate, useLocation } from 'react-router-dom';
 import { useAuthStore } from '../../stores/authStore';
@@ -18,6 +19,7 @@ import { usePreferencesStore } from '../../stores/preferencesStore';
 import { Sidebar } from './Sidebar';
 import { AppTour } from '../onboarding/AppTour';
 import { OnboardingWizard } from '../onboarding/OnboardingWizard';
+import { IdeaModal } from '../ideas/IdeaModal';
 import logoSrc from '../../assets/logo.png';
 
 export function AppLayout() {
@@ -28,6 +30,10 @@ export function AppLayout() {
   const location = useLocation();
   const isImpersonating = !!impersonationOriginal;
 
+  // ── Ideation State ──
+  const [ideaModalOpened, { open: openIdeaModal, close: closeIdeaModal }] = useDisclosure(false);
+  const ideationEnabled = currentOrg?.settings?.ideationEnabled === true;
+
   // ── Onboarding State ──
   const [showTour, setShowTour] = useState(false);
   const [showWizard, setShowWizard] = useState(false);
@@ -121,6 +127,13 @@ export function AppLayout() {
             {currentOrg && (
               <Text size="sm" c="dimmed">{currentOrg.name}</Text>
             )}
+            {ideationEnabled && (
+              <Tooltip label="Submit an idea">
+                <ActionIcon variant="default" size="lg" onClick={openIdeaModal} aria-label="Submit idea">
+                  <IconBulb size={18} />
+                </ActionIcon>
+              </Tooltip>
+            )}
             <Tooltip label={colorScheme === 'dark' ? 'Light mode' : 'Dark mode'}>
               <ActionIcon
                 variant="default"
@@ -209,6 +222,9 @@ export function AppLayout() {
       {/* ── Onboarding Components ── */}
       <AppTour run={showTour} onComplete={handleTourComplete} />
       <OnboardingWizard opened={showWizard} onComplete={handleWizardComplete} />
+
+      {/* ── Ideation Modal ── */}
+      <IdeaModal opened={ideaModalOpened} onClose={closeIdeaModal} />
     </AppShell>
   );
 }

frontend/src/pages/admin/AdminPage.tsx

@@ -11,7 +11,7 @@ import {
   IconCrown, IconPlus, IconArchive, IconChevronDown,
   IconCircleCheck, IconBan, IconArchiveOff, IconDashboard,
   IconHeartRateMonitor, IconSparkles, IconCalendar, IconActivity,
-  IconCurrencyDollar, IconClipboardCheck, IconLogin, IconEye,
+  IconCurrencyDollar, IconClipboardCheck, IconLogin, IconEye, IconBulb,
 } from '@tabler/icons-react';
 import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
 import { useNavigate } from 'react-router-dom';
@@ -211,6 +211,16 @@ export function AdminPage() {
     },
   });
 
+  const toggleIdeation = useMutation({
+    mutationFn: async ({ orgId, enabled }: { orgId: string; enabled: boolean }) => {
+      await api.put(`/admin/organizations/${orgId}/settings`, { ideationEnabled: enabled });
+    },
+    onSuccess: () => {
+      queryClient.invalidateQueries({ queryKey: ['admin-tenant-detail', selectedOrgId] });
+      queryClient.invalidateQueries({ queryKey: ['admin-orgs'] });
+    },
+  });
+
   const impersonateUser = useMutation({
     mutationFn: async (userId: string) => {
       const { data } = await api.post(`/admin/impersonate/${userId}`);
@@ -782,6 +792,27 @@ export function AdminPage() {
               </SimpleGrid>
             </Card>
 
+            <Card withBorder>
+              <Text fw={600} mb="xs">Feature Toggles</Text>
+              <Group justify="space-between">
+                <Group gap="xs">
+                  <IconBulb size={16} />
+                  <div>
+                    <Text size="sm">Ideation</Text>
+                    <Text size="xs" c="dimmed">Allow users to submit feature ideas</Text>
+                  </div>
+                </Group>
+                <Switch
+                  checked={tenantDetail.organization.settings?.ideationEnabled === true}
+                  onChange={(e) => {
+                    if (selectedOrgId) {
+                      toggleIdeation.mutate({ orgId: selectedOrgId, enabled: e.currentTarget.checked });
+                    }
+                  }}
+                />
+              </Group>
+            </Card>
+
             <Card withBorder>
               <Text fw={600} mb="xs">Subscription</Text>
               <Stack gap="xs">