feat: improve UX for Ollama 404 errors (missing model)

- src/ollama-client.ts: Detect HTTP 404 on /api/chat and throw a descriptive
  ApiError with the model name and the exact ollama pull command needed.

- src/error-handler.ts: For API_ERROR type, return the error message directly
  instead of prefixing with 'API error: ', so the user-friendly 404 message
  is shown cleanly in the Obsidian notice.

- tests/ollama-client.test.ts: Update 404 assertions to match the new
  descriptive error message.

main.js

@@ -8130,6 +8130,12 @@ var OllamaClient = class {
         signal: controller.signal
       });
       if (!response.ok) {
+        if (response.status === 404) {
+          throw new ApiError(
+            `Model "${this.model}" not found. Run \`ollama pull ${this.model}\` first.`,
+            404
+          );
+        }
         throw new ApiError(`Ollama API error: ${response.status}`, response.status);
       }
       if (!response.body) {
@@ -8233,6 +8239,12 @@ var OllamaClient = class {
         signal: controller.signal
       });
       if (!response.ok) {
+        if (response.status === 404) {
+          throw new ApiError(
+            `Model "${this.model}" not found. Run \`ollama pull ${this.model}\` first.`,
+            404
+          );
+        }
         throw new ApiError(`Ollama API error: ${response.status}`, response.status);
       }
       const data = await response.json();
@@ -8849,7 +8861,7 @@ var ErrorHandler = class {
       case "network_error" /* NETWORK_ERROR */:
         return "Connection error. Please check if Ollama is running.";
       case "api_error" /* API_ERROR */:
-        return `API error: ${error.message}`;
+        return error.message;
       case "validation_error" /* VALIDATION_ERROR */:
         return this.getUserFriendlyValidationMessage(error);
       case "streaming_error" /* STREAMING_ERROR */:

src/error-handler.ts

@@ -47,7 +47,7 @@ export class ErrorHandler {
       case ErrorType.NETWORK_ERROR:
         return 'Connection error. Please check if Ollama is running.';
       case ErrorType.API_ERROR:
-        return `API error: ${error.message}`;
+        return error.message;
       case ErrorType.VALIDATION_ERROR:
         return this.getUserFriendlyValidationMessage(error);
       case ErrorType.STREAMING_ERROR:

src/ollama-client.ts

@@ -146,6 +146,12 @@ export class OllamaClient {
       });
 
       if (!response.ok) {
+        if (response.status === 404) {
+          throw new ApiError(
+            `Model "${this.model}" not found. Run \`ollama pull ${this.model}\` first.`,
+            404
+          );
+        }
         throw new ApiError(`Ollama API error: ${response.status}`, response.status);
       }
 
@@ -270,6 +276,12 @@ export class OllamaClient {
       });
 
       if (!response.ok) {
+        if (response.status === 404) {
+          throw new ApiError(
+            `Model "${this.model}" not found. Run \`ollama pull ${this.model}\` first.`,
+            404
+          );
+        }
         throw new ApiError(`Ollama API error: ${response.status}`, response.status);
       }
 

tests/ollama-client.test.ts

@@ -214,7 +214,7 @@ describe('OllamaClient', () => {
       mockFetch.mockResolvedValue({ ok: false, status: 404 });
 
       await expect(client.streamChatAsPromise(mockMessages, mockTools)).rejects.toThrow(
-        'Ollama API error: 404'
+        'Model "llama3" not found. Run \`ollama pull llama3\` first.'
       );
     });
 
@@ -418,7 +418,7 @@ describe('OllamaClient', () => {
             /* consume */
           }
         })()
-      ).rejects.toThrow('Ollama API error: 404');
+      ).rejects.toThrow('Model "llama3" not found. Run \`ollama pull llama3\` first.');
     });
   });