feat(pitch-deck): English email templates, investor language preference, link-only invite mode

- Add English email template variants (greeting, message, closing, subject, CTA copy)
- Add `preferred_lang` column to `pitch_investors` — stored per investor, deck opens in that language by default
- Invite form: DE/EN language toggle that switches email defaults and pitch language setting
- Invite form: "Send email" toggle — when off, creates investor + returns magic link without sending email (for cold outreach attachment)
- `app/page.tsx`: initializes pitch language from investor's `preferred_lang` before first render (no flash)
- Migration 007 added to `/api/admin/migrate` route for production rollout

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

pitch-deck/app/api/admin/invite/route.ts

@@ -11,7 +11,7 @@ export async function POST(request: NextRequest) {
   const adminId = guard.kind === 'admin' ? guard.admin.id : null
 
   const body = await request.json().catch(() => ({}))
-  const { email, name, company, greeting, message, closing } = body
+  const { email, name, company, greeting, message, closing, lang = 'de', send_email = true } = body
 
   if (!email || typeof email !== 'string') {
     return NextResponse.json({ error: 'Email required' }, { status: 400 })
@@ -25,17 +25,20 @@ export async function POST(request: NextRequest) {
 
   const normalizedEmail = email.toLowerCase().trim()
 
+  const normalizedLang = lang === 'en' ? 'en' : 'de'
+
   // Upsert investor
   const { rows } = await pool.query(
-    `INSERT INTO pitch_investors (email, name, company)
-     VALUES ($1, $2, $3)
+    `INSERT INTO pitch_investors (email, name, company, preferred_lang)
+     VALUES ($1, $2, $3, $4)
      ON CONFLICT (email) DO UPDATE SET
        name = COALESCE(EXCLUDED.name, pitch_investors.name),
        company = COALESCE(EXCLUDED.company, pitch_investors.company),
+       preferred_lang = EXCLUDED.preferred_lang,
        status = CASE WHEN pitch_investors.status = 'revoked' THEN 'invited' ELSE pitch_investors.status END,
        updated_at = NOW()
      RETURNING id, status`,
-    [normalizedEmail, name || null, company || null],
+    [normalizedEmail, name || null, company || null, normalizedLang],
   )
 
   const investor = rows[0]
@@ -54,12 +57,21 @@ export async function POST(request: NextRequest) {
   const baseUrl = process.env.PITCH_BASE_URL || 'https://pitch.breakpilot.ai'
   const magicLinkUrl = `${baseUrl}/auth/verify?token=${token}`
 
-  await sendMagicLinkEmail(normalizedEmail, name || null, magicLinkUrl, greeting, message, closing)
+  if (send_email) {
+    await sendMagicLinkEmail(normalizedEmail, name || null, magicLinkUrl, greeting, message, closing, normalizedLang)
+  }
 
   await logAdminAudit(
     adminId,
     'investor_invited',
-    { email: normalizedEmail, name: name || null, company: company || null, expires_at: expiresAt.toISOString() },
+    {
+      email: normalizedEmail,
+      name: name || null,
+      company: company || null,
+      expires_at: expiresAt.toISOString(),
+      lang: normalizedLang,
+      send_email: !!send_email,
+    },
     request,
     investor.id,
   )
@@ -69,5 +81,6 @@ export async function POST(request: NextRequest) {
     investor_id: investor.id,
     email: normalizedEmail,
     expires_at: expiresAt.toISOString(),
+    magic_link_url: magicLinkUrl,
   })
 }