feat: Implement knowledge import feature for characters

- Added KnowledgeImport page for importing character knowledge from URLs.
- Integrated URL validation and error handling for unsupported websites.
- Created API endpoints for importing content from URLs and retrieving character knowledge.
- Enhanced VectorStoreService with logging and error handling for vector memory storage.
- Updated frontend to display knowledge sources and manage them effectively.
- Added support for fetching recent character knowledge as a fallback in similarity searches.
- Updated OpenAPI documentation to reflect new import functionality.

openapi/openapi.json

@@ -902,6 +902,59 @@
           "import"
         ]
       }
+    },
+    "/api/import/characters/{characterId}/url": {
+      "post": {
+        "operationId": "ImportController_importFromUrl",
+        "parameters": [
+          {
+            "name": "characterId",
+            "required": true,
+            "in": "path",
+            "description": "Character ID",
+            "schema": {
+              "type": "string"
+            }
+          }
+        ],
+        "requestBody": {
+          "required": true,
+          "content": {
+            "application/json": {
+              "schema": {
+                "$ref": "#/components/schemas/ImportUrlDto"
+              }
+            }
+          }
+        },
+        "responses": {
+          "201": {
+            "description": "URL content is being imported and processed",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/UploadResponseDto"
+                }
+              }
+            }
+          },
+          "400": {
+            "description": "Invalid URL or unsupported website"
+          },
+          "401": {
+            "description": "Unauthorized"
+          }
+        },
+        "security": [
+          {
+            "bearer": []
+          }
+        ],
+        "summary": "Import content from URL for character knowledge",
+        "tags": [
+          "import"
+        ]
+      }
     }
   },
   "info": {
@@ -1462,6 +1515,36 @@
           "userMessage",
           "assistantMessage"
         ]
+      },
+      "ImportUrlDto": {
+        "type": "object",
+        "properties": {
+          "url": {
+            "type": "string",
+            "description": "URL to import",
+            "example": "https://sakurazaka46.com/s/s46/diary/detail/68008"
+          }
+        },
+        "required": [
+          "url"
+        ]
+      },
+      "UploadResponseDto": {
+        "type": "object",
+        "properties": {
+          "knowledgeId": {
+            "type": "string",
+            "description": "Knowledge ID"
+          },
+          "message": {
+            "type": "string",
+            "description": "Status message"
+          }
+        },
+        "required": [
+          "knowledgeId",
+          "message"
+        ]
       }
     }
   }