feat: Add termination functionality for rental agreements

- Introduced new entity `CKuendigung` for managing terminations.
- Added fields for termination details including date, reason, type, and status.
- Implemented backend service to initiate terminations from rental agreements.
- Created frontend handler for termination actions with confirmation dialog.
- Updated metadata and layouts for `CKuendigung` to support new functionality.
- Added internationalization support for English and German languages.
- Enhanced existing entities to establish relationships with terminations.

custom/Espo/Custom/Resources/i18n/en_US/CKuendigung.json

@@ -0,0 +1,94 @@
+{
+    "fields": {
+        "kuendigungsdatum": "Termination Date",
+        "kuendigungsfrist": "Notice Period / Move-out Date",
+        "kuendigungsgrund": "Termination Reason",
+        "kuendigungsart": "Termination Type",
+        "kuendigenderPartei": "Terminating Party",
+        "status": "Status",
+        "zustellungsdatum": "Delivery Date",
+        "zustellungsart": "Delivery Method",
+        "rueckstandsbetrag": "Arrears Amount",
+        "monateMietrückstand": "Months of Arrears",
+        "schonfristGewaehrt": "Grace Period Granted",
+        "schonfristDatum": "Grace Period Date",
+        "besorgnisNichtRechtzeitigerAuszug": "Concern of Delayed Move-out",
+        "anmerkungen": "Notes",
+        "vmhMietverhltnis": "Rental Agreement",
+        "mietobjekt": "Property",
+        "vermieter": "Landlords",
+        "mieter": "Tenants",
+        "dokumenteKuendigung": "Documents",
+        "contactsKuendigung": "Shared Users"
+    },
+    "links": {
+        "vmhMietverhltnis": "Rental Agreement",
+        "mietobjekt": "Property",
+        "vermieter": "Landlords",
+        "mieter": "Tenants",
+        "dokumenteKuendigung": "Documents",
+        "contactsKuendigung": "Shared Users",
+        "meetings": "Meetings",
+        "calls": "Calls",
+        "tasks": "Tasks",
+        "emails": "Emails",
+        "collaborators": "Collaborators"
+    },
+    "labels": {
+        "Create CKuendigung": "Create Termination"
+    },
+    "options": {
+        "kuendigungsgrund": {
+            "Mietrückstand": "Rent Arrears",
+            "Eigenbedarf": "Personal Use",
+            "Fehlverhalten": "Misconduct",
+            "Verwertung": "Utilization",
+            "ZVG Eigenbedarf": "Foreclosure Personal Use",
+            "573a Abs. 1 (nicht mehr als 2 Whng.)": "§573a Para. 1 (max 2 units)",
+            "573a Abs. 2 (Einliegerwohnung)": "§573a Para. 2 (granny flat)",
+            "GewerbeOrdentlich": "Commercial Regular",
+            "Sonstige": "Other"
+        },
+        "kuendigungsart": {
+            "Ordentlich": "Regular",
+            "Außerordentlich (fristlos)": "Extraordinary (without notice)",
+            "Außerordentlich (mit sozialer Frist)": "Extraordinary (with social grace period)"
+        },
+        "kuendigenderPartei": {
+            "Vermieter": "Landlord",
+            "Mieter": "Tenant"
+        },
+        "status": {
+            "Entwurf": "Draft",
+            "Versendet": "Sent",
+            "Zugestellt": "Delivered",
+            "Anerkannt": "Acknowledged",
+            "Bestritten": "Disputed",
+            "Vollzogen": "Completed",
+            "Widerrufen": "Revoked"
+        },
+        "zustellungsart": {
+            "Persönlich": "Personal",
+            "Einschreiben": "Registered Mail",
+            "Gerichtlicher Zustellungsbevollmächtigter": "Court Process Server",
+            "E-Mail (sofern vereinbart)": "E-Mail (if agreed)",
+            "Sonstige": "Other"
+        }
+    },
+    "tooltips": {
+        "kuendigungsdatum": "Date when the termination was issued",
+        "kuendigungsfrist": "Date by which the tenancy should end (move-out date)",
+        "kuendigungsgrund": "Legal reason(s) for termination",
+        "kuendigungsart": "Type of termination: regular with notice period, extraordinary without notice, or with social grace period",
+        "kuendigenderPartei": "Which party terminates the tenancy",
+        "status": "Current processing status of the termination",
+        "zustellungsdatum": "Date when the termination was delivered to the recipient",
+        "zustellungsart": "Method of delivery (e.g., personal, registered mail)",
+        "rueckstandsbetrag": "Total amount of rent arrears (for termination due to rent arrears)",
+        "monateMietrückstand": "Number of months for which rent is in arrears",
+        "schonfristGewaehrt": "Was a grace period granted according to § 569 Para. 3 No. 2 BGB?",
+        "schonfristDatum": "Until what date does the grace period run?",
+        "besorgnisNichtRechtzeitigerAuszug": "Is there concern that the tenant will not move out on time? (Relevant for § 940a ZPO)",
+        "anmerkungen": "Additional notes and comments about the termination"
+    }
+}