Add application logging, SMTP email notifications, and supporting changes

Phase 5.4 — Application Logging:
- AppLog model + migration 0010 for unified audit/usage/error logging
- Usage logging middleware in app.py (after_request for /api/* requests)
- Error logging in 500 handler with traceback capture
- Audit logging for auth events (register, login, login_failed, logout,
  password_change) and admin actions (backup, restore, user_delete,
  registration_toggle, smtp_config, smtp_test)
- Admin log viewer (LogsView.vue) with stats, category/search/date
  filters, paginated table with expandable detail rows
- Admin logs API endpoints in admin.py (GET /logs, GET /logs/stats)
- Configurable retention via LOG_RETENTION_DAYS with hourly cleanup

Phase 5.5 — SMTP Email Notifications:
- aiosmtplib dependency for async email sending
- Email service (services/email.py) with STARTTLS/implicit TLS support
- Notification service (services/notifications.py) for security alerts
  and task due date reminders with per-user preferences
- Admin SMTP config endpoints (GET/PUT /api/admin/smtp, POST test)
- SMTP config in Config class with env var + Docker secret support
- Settings UI: notification preferences for all users, SMTP config
  section for admin with test email

Other changes:
- stream_chat() now accepts optional options dict (for num_predict)
- Increase assist MAX_BODY_CHARS from 3000 to 8000
- get_user_by_username() added to auth service
- apiStreamPost buffer processing refactored for robustness
- AppHeader: admin Logs nav link
- Router: /admin/logs route

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

src/fabledassistant/routes/admin.py

@@ -1,6 +1,6 @@
 import json
 
-from quart import Blueprint, Response, jsonify, request
+from quart import Blueprint, Response, g, jsonify, request
 
 from fabledassistant.auth import admin_required, login_required, get_current_user_id
 from fabledassistant.services.auth import (
@@ -14,6 +14,9 @@ from fabledassistant.services.backup import (
     export_user_backup,
     restore_full_backup,
 )
+from fabledassistant.services.email import SMTP_SETTING_KEYS, get_smtp_config, send_test_email
+from fabledassistant.services.logging import get_logs, get_log_stats, log_audit
+from fabledassistant.services.settings import set_settings_batch
 
 admin_bp = Blueprint("admin", __name__, url_prefix="/api/admin")
 
@@ -26,13 +29,13 @@ async def backup():
 
     if scope == "full":
         # Full backup requires admin
-        from quart import g
         if g.user.role != "admin":
             return jsonify({"error": "Admin access required for full backup"}), 403
         data = await export_full_backup()
     else:
         data = await export_user_backup(uid)
 
+    await log_audit("backup", user_id=uid, username=g.user.username, ip_address=request.remote_addr, details={"scope": scope})
     return Response(
         json.dumps(data, indent=2, default=str),
         content_type="application/json",
@@ -50,6 +53,8 @@ async def restore():
         return jsonify({"error": "No backup data provided"}), 400
 
     stats = await restore_full_backup(data)
+    uid = get_current_user_id()
+    await log_audit("restore", user_id=uid, username=g.user.username, ip_address=request.remote_addr, details={"stats": stats})
     return jsonify({"status": "ok", "stats": stats})
 
 
@@ -70,6 +75,7 @@ async def remove_user(user_id: int):
     deleted = await delete_user(user_id)
     if not deleted:
         return jsonify({"error": "User not found"}), 404
+    await log_audit("user_delete", user_id=current_uid, username=g.user.username, ip_address=request.remote_addr, details={"deleted_user_id": user_id})
     return jsonify({"status": "ok"})
 
 
@@ -90,4 +96,82 @@ async def toggle_registration():
 
     uid = get_current_user_id()
     await set_registration_open(uid, bool(open_val))
+    await log_audit("registration_toggle", user_id=uid, username=g.user.username, ip_address=request.remote_addr, details={"open": bool(open_val)})
     return jsonify({"status": "ok", "open": bool(open_val)})
+
+
+@admin_bp.route("/smtp", methods=["GET"])
+@admin_required
+async def get_smtp():
+    config = await get_smtp_config()
+    # Mask password
+    if config.get("smtp_password"):
+        config["smtp_password"] = "********"
+    return jsonify(config)
+
+
+@admin_bp.route("/smtp", methods=["PUT"])
+@admin_required
+async def update_smtp():
+    data = await request.get_json()
+    uid = get_current_user_id()
+
+    settings_to_save = {}
+    for key in SMTP_SETTING_KEYS:
+        if key in data:
+            # Skip password if it's the mask placeholder
+            if key == "smtp_password" and data[key] == "********":
+                continue
+            settings_to_save[key] = str(data[key])
+
+    if settings_to_save:
+        await set_settings_batch(uid, settings_to_save)
+    await log_audit("smtp_config", user_id=uid, username=g.user.username, ip_address=request.remote_addr)
+    return jsonify({"status": "ok"})
+
+
+@admin_bp.route("/smtp/test", methods=["POST"])
+@admin_required
+async def test_smtp():
+    data = await request.get_json()
+    recipient = (data.get("recipient") or "").strip()
+    if not recipient:
+        return jsonify({"error": "Recipient email is required"}), 400
+
+    uid = get_current_user_id()
+    try:
+        await send_test_email(recipient)
+        await log_audit("smtp_test", user_id=uid, username=g.user.username, ip_address=request.remote_addr, details={"recipient": recipient})
+        return jsonify({"status": "ok"})
+    except Exception as e:
+        return jsonify({"error": str(e)}), 500
+
+
+@admin_bp.route("/logs", methods=["GET"])
+@admin_required
+async def list_logs():
+    category = request.args.get("category")
+    user_id = request.args.get("user_id", type=int)
+    search = request.args.get("search")
+    date_from = request.args.get("date_from")
+    date_to = request.args.get("date_to")
+    limit = request.args.get("limit", 50, type=int)
+    offset = request.args.get("offset", 0, type=int)
+
+    logs, total = await get_logs(
+        category=category,
+        user_id=user_id,
+        search=search,
+        date_from=date_from,
+        date_to=date_to,
+        limit=min(limit, 200),
+        offset=offset,
+    )
+    return jsonify({"logs": logs, "total": total})
+
+
+@admin_bp.route("/logs/stats", methods=["GET"])
+@admin_required
+async def log_stats():
+    stats = await get_log_stats()
+    return jsonify(stats)