feat: add pin/unpin functionality to chat history

Adds pin/unpin functionality to the chat history sidebar, allowing users to keep important conversations readily accessible. This improves user experience and helps organize past interactions.

This feature includes:
- Pin/unpin buttons in the chat history sidebar.
- Updated database schema to include `is_pinned` field for chat history items.
- Localized translations for pin/unpin actions.
- Updated UI to display pinned items at the top of the list.

src/assets/locale/no/common.json

@@ -41,6 +41,7 @@
     "webSearch": "Søker på internett",
     "regenerate": "Regenerer",
     "edit": "Endre",
+    "delete": "Slett",
     "saveAndSubmit": "Lagre & Send inn",
     "editMessage": {
         "placeholder": "Skriv en melding..."
@@ -102,5 +103,14 @@
         "custom": "Egendefinert"
     },
     "citations": "Sitater",
-    "downloadCode": "Last ned kode"
+    "downloadCode": "Last ned kode",
+    "date": {
+        "pinned": "Festet",
+        "today": "I dag",
+        "yesterday": "I går",
+        "last7Days": "Siste 7 dager",
+        "older": "Eldre"
+    },
+    "pin": "Fest",
+    "unpin": "Løsne"
 }

src/assets/locale/no/knowledge.json

@@ -10,9 +10,6 @@
     "expandedColumns": {
         "name": "Navn"
     },
-    "tooltip": {
-        "delete": "Slett"
-    },
     "confirm": {
         "delete": "Er du sikker på at du vil slette denne kunnskapen?"
     },