feat: Replace mock WhatsApp with real Meta Graph API webhook

- POST /api/whatsapp/webhook handles Meta verification (hub.challenge)
- Inbound text messages create tickets via create_ticket()
- Auto-reply confirmation sent back via Meta Graph API
- WhatsApp messages logged with ticket linkage in whatsapp_log
- Added WHATSAPP_PHONE_NUMBER_ID, WHATSAPP_ACCESS_TOKEN, WHATSAPP_VERIFY_TOKEN config
- Kept /mock-log debug endpoint for backward compatibility
- Graceful degradation: logs message even if ticket/reply fails

app/schemas/whatsapp.py

@@ -1,10 +1,69 @@
-"""Pydantic schemas for mock WhatsApp endpoint."""
+"""Pydantic schemas for Meta WhatsApp webhook."""
 
 from __future__ import annotations
 
 from datetime import datetime
 
-from pydantic import BaseModel
+from pydantic import BaseModel, Field
+
+
+# ── Meta Webhook Verification ────────────────────────────────────────
+class WebhookVerificationResponse(BaseModel):
+    challenge: str
+
+
+# ── Inbound Message Parsing ─────────────────────────────────────────
+class MessageText(BaseModel):
+    text: str
+
+
+class Message(BaseModel):
+    from_field: str = Field(alias="from")
+    id: str | None = None
+    text: MessageText | None = None
+    type: str | None = None
+
+
+class Contact(BaseModel):
+    wa_id: str | None = None
+    profile: dict | None = None
+
+
+class EntryMessagesItem(BaseModel):
+    id: str | None = None
+    message: Message | None = None
+    contacts: list[Contact] | None = None
+    timestamp: str | None = None
+
+
+class Entry(BaseModel):
+    id: str | None = None
+    changes: list[EntryMessagesItem] | None = None
+    metadata: dict | None = None
+
+
+class MetaWebhookRequest(BaseModel):
+    object: str | None = None
+    entry: list[Entry] | None = None
+
+
+# ── Auto-reply ──────────────────────────────────────────────────────
+class WhatsAppReplyResponse(BaseModel):
+    success: bool
+    message: str
+
+
+# ── Legacy mock schemas (kept for /mock-log endpoint) ───────────────
+class MockWhatsAppLogEntry(BaseModel):
+    id: int
+    from_number: str
+    message_text: str
+    wa_message_id: str | None
+    ticket_id: int | None
+    ticket_number: str | None
+    received_at: datetime
+
+    model_config = {"from_attributes": True}
 
 
 class MockWhatsAppRequest(BaseModel):
@@ -16,13 +75,3 @@ class MockWhatsAppRequest(BaseModel):
 class MockWhatsAppResponse(BaseModel):
     status: str = "received"
     message: str = "Command logged successfully"
-
-
-class MockWhatsAppLogEntry(BaseModel):
-    id: int
-    command: str
-    from_number: str | None
-    ticket_id: int | None
-    received_at: datetime
-
-    model_config = {"from_attributes": True}