feat(pitch-deck): admin UI for investor + financial-model management

Adds /pitch-admin dashboard with real admin accounts (bcrypt) and full
audit attribution for every state-changing action.

Backend:
- pitch_admins + pitch_admin_sessions tables (migration 002)
- pitch_audit_logs.admin_id + target_investor_id columns
- lib/admin-auth.ts: bcryptjs hashing, single-session enforcement,
  jose JWT with 'pitch-admin' audience claim, requireAdmin guard
- logAudit extended to accept admin_id and target_investor_id
- middleware.ts: gates /pitch-admin/* and /api/admin/* on the admin
  cookie (with bearer-secret fallback for CLI compatibility)
- 14 API routes under /api/admin-auth and /api/admin (login, logout,
  me, dashboard, investors[id] CRUD + resend, admins CRUD,
  fm scenarios + assumptions PATCH)
- Existing /api/admin/{invite,investors,revoke,audit-logs} migrated
  to requireAdmin and now log with admin_id + target_investor_id
- scripts/create-admin.ts CLI bootstrap (npm run admin:create)

Frontend:
- /pitch-admin/login + /pitch-admin/(authed) route group
- AdminShell with sidebar nav + StatCard + AuditLogTable components
- Dashboard with KPIs, recent logins, recent activity
- Investors list with search/filter + resend/revoke inline actions
- Investor detail with inline edit + per-investor audit timeline
- Audit log viewer with actor/action/date filters + pagination
- Financial model scenario list + per-scenario assumption editor
  (categorized, inline edit, before/after diff in audit)
- Admins management (add, deactivate, reset password)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

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

@@ -1,22 +1,23 @@
 import { NextRequest, NextResponse } from 'next/server'
 import pool from '@/lib/db'
-import { validateAdminSecret, generateToken, logAudit, getClientIp } from '@/lib/auth'
+import { generateToken } from '@/lib/auth'
+import { requireAdmin, logAdminAudit } from '@/lib/admin-auth'
 import { sendMagicLinkEmail } from '@/lib/email'
 import { checkRateLimit, RATE_LIMITS } from '@/lib/rate-limit'
 
 export async function POST(request: NextRequest) {
-  if (!validateAdminSecret(request)) {
-    return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
-  }
+  const guard = await requireAdmin(request)
+  if (guard.kind === 'response') return guard.response
+  const adminId = guard.kind === 'admin' ? guard.admin.id : null
 
-  const body = await request.json()
+  const body = await request.json().catch(() => ({}))
   const { email, name, company } = body
 
   if (!email || typeof email !== 'string') {
     return NextResponse.json({ error: 'Email required' }, { status: 400 })
   }
 
-  // Rate limit by email
+  // Rate limit by email (3/hour)
   const rl = checkRateLimit(`magic-link:${email.toLowerCase()}`, RATE_LIMITS.magicLink)
   if (!rl.allowed) {
     return NextResponse.json({ error: 'Too many invites for this email. Try again later.' }, { status: 429 })
@@ -34,7 +35,7 @@ export async function POST(request: NextRequest) {
        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],
   )
 
   const investor = rows[0]
@@ -47,17 +48,21 @@ export async function POST(request: NextRequest) {
   await pool.query(
     `INSERT INTO pitch_magic_links (investor_id, token, expires_at)
      VALUES ($1, $2, $3)`,
-    [investor.id, token, expiresAt]
+    [investor.id, token, expiresAt],
   )
 
-  // Build magic link URL
   const baseUrl = process.env.PITCH_BASE_URL || 'https://pitch.breakpilot.ai'
   const magicLinkUrl = `${baseUrl}/auth/verify?token=${token}`
 
-  // Send email
   await sendMagicLinkEmail(normalizedEmail, name || null, magicLinkUrl)
 
-  await logAudit(investor.id, 'magic_link_sent', { email: normalizedEmail }, request)
+  await logAdminAudit(
+    adminId,
+    'investor_invited',
+    { email: normalizedEmail, name: name || null, company: company || null, expires_at: expiresAt.toISOString() },
+    request,
+    investor.id,
+  )
 
   return NextResponse.json({
     success: true,