feat: Kundenportal-Ausbau - Tabs, Projekt-Einblicke, Git-Zeiterfassung, Rechnungen, Chat

Kunden-Dashboard:
- Tab-Navigation: Projekte | Was wurde gemacht | Rechnungen | Chat
- Projekt-Details pro Projekt: letzte Git-Commits (Titel+Beschreibung),
  Projektgroesse, Datei-Uebersicht (Top-Level aggregiert), Ticket-Arbeiten
- Rechnungen: gestylte Liste mit Status-Pillen, Ansehen/Zahlen-Link,
  PDF-Download ueber Server-Proxy (IDOR-geschuetzt)
- Chat mit dem Webklar-Team (Polling, Ungelesen-Badge, viewAs blockiert)

Admin-Dashboard:
- Chat-Tab: Konversationsliste + Thread + Antwortfeld, Ungelesen-Badge

Backend:
- giteaAdmin: getRepoInfo, listRepoCommits, getRepoTreeSummary
- projectInsights: 5-min-Cache, Invalidierung per Gitea-Webhook
- /api/projects/:id/git|files|work mit Ownership-Check (404)
- /api/chat/* (Kunde) + /api/portal-admin/chats/* (Admin), portalMessages-Collection
- mailer: E-Mail-Benachrichtigung an Admins bei Kundennachricht (15-min-Throttle)
- gitWorksheet: dd.mm.yyyy, voller Commit-Body, startTime leer (Zeit-Nachtrag),
  Auto-Webpage-Ticket bei Push auf Projekt ohne Ticket (ensureProjectTicket)
- customerActivity: Git-Push-Eintraege fuer Kunden sichtbar

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

server/routes/portalAdmin.js

@@ -6,13 +6,16 @@ import {
   setPortalSession,
 } from '../middleware/session.js'
 import {
+  createDocument,
   getDocument,
   listDocuments,
   updateDocument,
   Query,
+  ID,
 } from '../services/appwriteAdmin.js'
 import { getCustomerActivity } from '../services/customerActivity.js'
 import { listInvoicesForClient } from '../services/invoiceNinja.js'
+import { sanitizeMessage } from './chat.js'
 
 const router = Router()
 
@@ -222,6 +225,120 @@ router.get('/customers/:customerId/invoices', async (req, res) => {
   }
 })
 
+// ------------------------------------------------------------------- Chat --
+router.get('/chats', async (_req, res) => {
+  try {
+    const [messages, customers] = await Promise.all([
+      listDocuments(config.collections.portalMessages, [
+        Query.orderDesc('createdAt'),
+        Query.limit(500),
+      ]),
+      listDocuments(config.collections.customers, [Query.limit(500)]),
+    ])
+    const nameById = customerNameMap(customers)
+
+    const byCustomer = new Map()
+    for (const msg of messages) {
+      const entry = byCustomer.get(msg.customerId) || {
+        customerId: msg.customerId,
+        customerName: nameById[msg.customerId] || msg.customerId,
+        lastText: msg.text || '',
+        lastSender: msg.sender || '',
+        lastAt: msg.createdAt || '',
+        unreadFromCustomer: 0,
+      }
+      if (msg.sender === 'customer' && !msg.readByAdmin) entry.unreadFromCustomer += 1
+      byCustomer.set(msg.customerId, entry)
+    }
+
+    const chats = [...byCustomer.values()].sort((a, b) =>
+      String(b.lastAt).localeCompare(String(a.lastAt))
+    )
+    return res.json({ chats })
+  } catch (err) {
+    return res.status(500).json({ error: err.message || 'Chats konnten nicht geladen werden' })
+  }
+})
+
+router.get('/chats/unread-count', async (_req, res) => {
+  try {
+    const docs = await listDocuments(config.collections.portalMessages, [
+      Query.equal('readByAdmin', false),
+      Query.equal('sender', 'customer'),
+      Query.limit(100),
+    ])
+    return res.json({ unread: docs.length })
+  } catch {
+    return res.json({ unread: 0 })
+  }
+})
+
+router.get('/chats/:customerId/messages', async (req, res) => {
+  try {
+    const queries = [
+      Query.equal('customerId', req.params.customerId),
+      Query.orderAsc('createdAt'),
+      Query.limit(200),
+    ]
+    const since = String(req.query.since || '').trim()
+    if (since) queries.push(Query.greaterThan('createdAt', since))
+
+    const docs = await listDocuments(config.collections.portalMessages, queries)
+    return res.json({ messages: docs.map(sanitizeMessage) })
+  } catch (err) {
+    return res.status(500).json({ error: err.message || 'Nachrichten konnten nicht geladen werden' })
+  }
+})
+
+router.post('/chats/:customerId/messages', async (req, res) => {
+  const text = String(req.body?.text || '').trim()
+  if (!text || text.length > 2000) {
+    return res.status(400).json({ error: 'Nachricht muss zwischen 1 und 2000 Zeichen lang sein.' })
+  }
+
+  try {
+    const customer = await getDocument(config.collections.customers, req.params.customerId).catch(() => null)
+    if (!customer) {
+      return res.status(404).json({ error: 'Kunde nicht gefunden' })
+    }
+
+    const session = req.session
+    const doc = await createDocument(
+      config.collections.portalMessages,
+      {
+        customerId: customer.$id,
+        sender: 'admin',
+        senderName: session.adminName || session.name || 'Webklar-Team',
+        text,
+        readByAdmin: true,
+        readByCustomer: false,
+        createdAt: new Date().toISOString(),
+      },
+      ID.unique()
+    )
+    return res.status(201).json({ message: sanitizeMessage(doc) })
+  } catch (err) {
+    return res.status(500).json({ error: err.message || 'Nachricht konnte nicht gesendet werden' })
+  }
+})
+
+router.post('/chats/:customerId/read', async (req, res) => {
+  try {
+    const docs = await listDocuments(config.collections.portalMessages, [
+      Query.equal('customerId', req.params.customerId),
+      Query.equal('readByAdmin', false),
+      Query.equal('sender', 'customer'),
+      Query.limit(100),
+    ])
+    for (const doc of docs) {
+      await updateDocument(config.collections.portalMessages, doc.$id, { readByAdmin: true })
+    }
+    return res.json({ updated: docs.length })
+  } catch (err) {
+    return res.status(500).json({ error: err.message || 'Fehler beim Markieren' })
+  }
+})
+
 // ------------------------------------------------------- Als Kunde ansehen --
 router.post('/view-as/:customerId', async (req, res) => {
   try {