feat: Allow specifying mmproj path during model loading

The `loadOptions` interface in `AIEngine.ts` now includes an optional `mmprojPath` property.  This allows users to provide a path to their MMProject file when loading a model, which is required for certain model types.  The `llamacpp-extension/src/index.ts` has been updated to pass this option to the llamacpp server if provided.

core/src/browser/extensions/engines/AIEngine.ts

@@ -103,6 +103,7 @@ export type listResult = modelInfo[]
 export interface loadOptions {
   modelId: string
   modelPath: string
+  mmprojPath?: string
   port?: number
 }
 
@@ -181,7 +182,7 @@ export abstract class AIEngine extends BaseExtension {
   /**
    * Unloads a model from memory
    */
-  abstract unload(opts: unloadOptions): Promise<unloadResult>
+  abstract unload(sessionId: string): Promise<unloadResult>
 
   /**
    * Sends a chat request to the model

extensions/llamacpp-extension/src/index.ts

@@ -343,6 +343,9 @@ export default class llamacpp_extension extends AIEngine {
     args.push('-m', opts.modelPath)
     args.push('-a', opts.modelId)
     args.push('--port', String(opts.port || 8080)) // Default port if not specified
+    if (opts.mmprojPath) {
+        args.push('--mmproj', opts.mmprojPath)
+    }
 
     if (cfg.ctx_size !== undefined) {
       args.push('-c', String(cfg.ctx_size))