feat(notifications): add Telegram test button

New "Test senden" button next to Speichern posts current form
credentials (not DB) to /actions/notifications/test, which fires a
test message and redirects back with a flash chip showing the outcome
(including the Telegram API's error description on failure).

telegram_send is now public and returns (ok, detail) so the UI can
surface real error messages ("chat not found", "Unauthorized", etc.).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

web/notifications.py

@@ -18,7 +18,9 @@ logger = logging.getLogger("web.notifications")
 EventType = str  # 'match' | 'apply_ok' | 'apply_fail'
 
 
-def _telegram_send(token: str, chat_id: str, text: str) -> bool:
+def telegram_send(token: str, chat_id: str, text: str) -> tuple[bool, str]:
+    """Send a Telegram message. Returns (ok, detail) — detail is the Telegram
+    API's `description` on failure, or a short error string, or "ok"."""
     try:
         r = requests.post(
             f"https://api.telegram.org/bot{token}/sendMessage",
@@ -26,13 +28,17 @@ def _telegram_send(token: str, chat_id: str, text: str) -> bool:
                   "disable_web_page_preview": True},
             timeout=10,
         )
-        if not r.ok:
+        if r.ok:
+            return True, "ok"
+        try:
+            detail = r.json().get("description") or f"HTTP {r.status_code}"
+        except ValueError:
+            detail = f"HTTP {r.status_code}"
         logger.warning("telegram send failed: %s %s", r.status_code, r.text[:200])
-            return False
+        return False, detail
-        return True
     except requests.RequestException as e:
         logger.warning("telegram unreachable: %s", e)
-        return False
+        return False, str(e)
 
 
 def _should_notify(notif, event: EventType) -> bool:
@@ -57,7 +63,7 @@ def notify_user(user_id: int, event: EventType, *,
             token = notif["telegram_bot_token"]
             chat = notif["telegram_chat_id"]
             if token and chat:
-                _telegram_send(token, chat, body_markdown or body_plain)
+                telegram_send(token, chat, body_markdown or body_plain)
     except Exception:
         logger.exception("notify_user failed for user=%s event=%s", user_id, event)
 

web/routes/einstellungen.py

@@ -1,5 +1,7 @@
 """Einstellungen (settings) tab: profile, filter info, notifications, partner,
 account, plus the related action endpoints."""
+from urllib.parse import quote
+
 from fastapi import APIRouter, Depends, Form, HTTPException, Request
 from fastapi.responses import HTMLResponse, RedirectResponse
 
@@ -7,6 +9,7 @@ import db
 from auth import current_user, hash_password, require_csrf, require_user
 from common import base_context, client_ip, templates
 from matching import row_to_dict
+from notifications import telegram_send
 
 
 router = APIRouter()
@@ -39,6 +42,8 @@ def tab_settings(request: Request, section: str):
         ctx["filters"] = row_to_dict(db.get_filters(u["id"]))
     elif section == "benachrichtigungen":
         ctx["notifications"] = db.get_notifications(u["id"])
+        ctx["notif_flash"] = request.query_params.get("flash") or ""
+        ctx["notif_flash_detail"] = request.query_params.get("detail") or ""
     elif section == "partner":
         ctx["partner"] = db.get_partner_user(u["id"])
         ctx["partner_profile"] = db.get_profile(ctx["partner"]["id"]) if ctx["partner"] else None
@@ -105,6 +110,34 @@ async def action_notifications(request: Request, user=Depends(require_user)):
     return RedirectResponse("/einstellungen/benachrichtigungen", status_code=303)
 
 
+@router.post("/actions/notifications/test")
+async def action_notifications_test(request: Request, user=Depends(require_user)):
+    """Send a test Telegram message using the credentials currently in the
+    form (not the DB), so unsaved edits can be verified before saving."""
+    form = await request.form()
+    require_csrf(user["id"], form.get("csrf", ""))
+    token = (form.get("telegram_bot_token") or "").strip()
+    chat_id = (form.get("telegram_chat_id") or "").strip()
+    if not token or not chat_id:
+        return RedirectResponse(
+            "/einstellungen/benachrichtigungen?flash=test_missing",
+            status_code=303,
+        )
+    ok, detail = telegram_send(
+        token, chat_id, f"*lazyflat* Testnachricht ✅\nfür `{user['username']}`",
+    )
+    db.log_audit(
+        user["username"], "notifications.tested",
+        f"ok={ok} detail={detail[:120]}",
+        user_id=user["id"], ip=client_ip(request),
+    )
+    flash = "test_ok" if ok else "test_fail"
+    target = f"/einstellungen/benachrichtigungen?flash={flash}"
+    if not ok:
+        target += f"&detail={quote(detail[:200])}"
+    return RedirectResponse(target, status_code=303)
+
+
 @router.post("/actions/account/password")
 async def action_password(
     request: Request,

web/templates/_settings_notifications.html

@@ -3,6 +3,18 @@
     Wähle einen Kanal und entscheide, welche Events dich erreichen sollen.
 </p>
 
+{% if notif_flash %}
+<div class="chip mb-4
+    {% if notif_flash == 'test_ok' %}chip-ok
+    {% else %}chip-bad
+    {% endif %}">
+    {% if notif_flash == 'test_ok' %}Testnachricht gesendet.
+    {% elif notif_flash == 'test_missing' %}Bot-Token und Chat-ID eintragen, um zu testen.
+    {% elif notif_flash == 'test_fail' %}Test fehlgeschlagen{% if notif_flash_detail %}: {{ notif_flash_detail }}{% endif %}.
+    {% endif %}
+</div>
+{% endif %}
+
 <form method="post" action="/actions/notifications" class="space-y-4 max-w-xl"
       autocomplete="off" data-lpignore="true" data-1p-ignore data-bwignore data-form-type="other">
     <input type="hidden" name="csrf" value="{{ csrf }}">
@@ -42,5 +54,9 @@
         </label>
     </div>
 
+    <div class="flex gap-2">
         <button class="btn btn-primary" type="submit">Speichern</button>
+        <button class="btn btn-ghost" type="submit"
+                formaction="/actions/notifications/test" formnovalidate>Test senden</button>
+    </div>
 </form>