feat(Mountain): implement Cocoon gRPC file system operations and command registry

This commit implements the remaining stubbed operations in the CocoonService gRPC server, replacing Status::unimplemented returns with working implementations:

- **File System Operations**: read_file, write_file, stat, readdir now delegate to tokio::fs with proper URI-to-path parsing. delete_file, rename_file, copy_file, create_directory implemented with atomic parent directory creation.
- **find_files**: Implements glob pattern matching using globset crate, walking workspace folders from ApplicationState.
- **git_exec**: Spawns native git process with provided args, captures stdout/stderr, returns exit code and output lines.
- **open_terminal**: Wires to MountainEnvironment::CreateTerminal using TerminalProvider.
- **Command Registration**: Wires RegisterCommand/UnregisterCommand to CommandExecutor instead of stub logging.
- **Language Feature Providers**: All 15+ provider registration methods now call RegisterProvider to store metadata in ApplicationState.Extension.ProviderRegistration.
- **Workspace Folders**: Initialize handler now parses workspace_folders from init payload and stores in ApplicationState.Workspace.
- **Extension Queries**: get_extension and get_all_extensions now query ApplicationState via ExtensionManagementService.

This removes the TODO placeholders for these operations and enables the full gRPC service contract between Mountain and Cocoon.

Author: NikolaRHristov

Source/IPC/WindServiceHandlers.rs

@@ -183,9 +183,11 @@ type ConfigurationOverridesDTO = ConfigurationOverridesDTOModule::ConfigurationO
 type ConfigurationTarget = ConfigurationTargetModule::ConfigurationTarget;
 
 use CommonLibrary::{
+	Command::CommandExecutor::CommandExecutor,
 	Configuration::ConfigurationProvider::ConfigurationProvider,
 	Environment::Requires::Requires,
 	Error::CommonError::CommonError,
+	ExtensionManagement::ExtensionManagementService::ExtensionManagementService,
 	FileSystem::{FileSystemReader::FileSystemReader, FileSystemWriter::FileSystemWriter},
 	Storage::StorageProvider::StorageProvider,
 };
@@ -234,6 +236,15 @@ pub async fn mountain_ipc_invoke(app_handle:AppHandle, command:String, args:Vec<
 		// Workbench commands
 		"workbench:getConfiguration" => handle_workbench_configuration(runtime.inner().clone(), args).await,
 
+		// Command registry commands
+		"commands:execute" => handle_commands_execute(runtime.inner().clone(), args).await,
+		"commands:getAll" => handle_commands_get_all(runtime.inner().clone()).await,
+
+		// Extension host commands
+		"extensions:getAll" => handle_extensions_get_all(runtime.inner().clone()).await,
+		"extensions:get" => handle_extensions_get(runtime.inner().clone(), args).await,
+		"extensions:isActive" => handle_extensions_is_active(runtime.inner().clone(), args).await,
+
 		// IPC status commands
 		"mountain_get_status" => {
 			let status = json!({
@@ -818,3 +829,86 @@ pub fn register_wind_ipc_handlers(app_handle:&tauri::AppHandle) -> Result<(), St
 
 	Ok(())
 }
+
+// ============================================================================
+// Command Registry Handlers
+// ============================================================================
+
+/// Execute a command by ID, dispatching to Mountain's CommandExecutor.
+async fn handle_commands_execute(runtime:Arc<ApplicationRunTime>, args:Vec<Value>) -> Result<Value, String> {
+	let CommandId = args
+		.first()
+		.and_then(|V| V.as_str())
+		.ok_or_else(|| "commands:execute requires string command_id as first argument".to_string())?
+		.to_string();
+
+	let Argument = args.get(1).cloned().unwrap_or(Value::Null);
+
+	debug!("[WindServiceHandlers] commands:execute id={}", CommandId);
+
+	runtime
+		.Environment
+		.ExecuteCommand(CommandId, Argument)
+		.await
+		.map_err(|Error| format!("commands:execute failed: {}", Error))
+}
+
+/// Return all registered command IDs from Mountain's CommandRegistry.
+async fn handle_commands_get_all(runtime:Arc<ApplicationRunTime>) -> Result<Value, String> {
+	let Commands = runtime
+		.Environment
+		.GetAllCommands()
+		.await
+		.map_err(|Error| format!("commands:getAll failed: {}", Error))?;
+
+	Ok(json!(Commands))
+}
+
+// ============================================================================
+// Extension Host Handlers
+// ============================================================================
+
+/// Return metadata for all scanned extensions.
+async fn handle_extensions_get_all(runtime:Arc<ApplicationRunTime>) -> Result<Value, String> {
+	let Extensions = runtime
+		.Environment
+		.GetExtensions()
+		.await
+		.map_err(|Error| format!("extensions:getAll failed: {}", Error))?;
+
+	Ok(json!(Extensions))
+}
+
+/// Return metadata for a single extension by ID.
+async fn handle_extensions_get(runtime:Arc<ApplicationRunTime>, args:Vec<Value>) -> Result<Value, String> {
+	let Id = args
+		.first()
+		.and_then(|V| V.as_str())
+		.ok_or_else(|| "extensions:get requires string id as first argument".to_string())?
+		.to_string();
+
+	let Extension = runtime
+		.Environment
+		.GetExtension(Id)
+		.await
+		.map_err(|Error| format!("extensions:get failed: {}", Error))?;
+
+	Ok(Extension.unwrap_or(Value::Null))
+}
+
+/// Check whether an extension is currently active (scanned and present).
+async fn handle_extensions_is_active(runtime:Arc<ApplicationRunTime>, args:Vec<Value>) -> Result<Value, String> {
+	let Id = args
+		.first()
+		.and_then(|V| V.as_str())
+		.ok_or_else(|| "extensions:isActive requires string id as first argument".to_string())?
+		.to_string();
+
+	let Extension = runtime
+		.Environment
+		.GetExtension(Id)
+		.await
+		.map_err(|Error| format!("extensions:isActive failed: {}", Error))?;
+
+	Ok(json!(Extension.is_some()))
+}