chore(Mountain): Add payload preview to notif-drop logging and register benign ENOENT paths

Two logging improvements for Mountain's developer diagnostics:

1. **Notif-drop payload preview**: When a notification falls through to the Cocoon event handler, include a truncated payload preview (160 bytes max) in the dev log. This helps diagnose which new upstream notifications are reaching the catch-all without needing a second debug run.

2. **Benign ENOENT paths**: Register additional file paths that commonly return ENOENT but aren't errors:
   - MCP config files (.vscode/mcp.json, .mcp.json)
   - User snippets and keybindings (/User/snippets, /User/keybindings.json)
   - AI-generated workspace storage (aiGeneratedWorkspaces.json)
   - Git config for non-repo folders (/.git/config)

These paths reduce noise in dev logs while preserving signal for genuine file-access issues.

Author: NikolaRHristov

Source/IPC/DevLog.rs

@@ -487,6 +487,8 @@ const BENIGN_ENOENT_SUBSTRINGS:&[&str] = &[
 	".vscode/launch.json",
 	".vscode/extensions.json",
 	".vscode/tasks.json",
+	".vscode/mcp.json",
+	".mcp.json",
 	"agentPlugins",
 	"agent-plugins",
 	"chatEditingSessions",
@@ -501,6 +503,15 @@ const BENIGN_ENOENT_SUBSTRINGS:&[&str] = &[
 	// `resolve_userdata`.
 	"/User/tasks.json",
 	"/User/mcp.json",
+	"/User/snippets",
+	"/User/keybindings.json",
+	// Workspace-storage sidecar files the workbench stats on every project
+	// open - absent until the AI-generated-workspace feature writes one.
+	"aiGeneratedWorkspaces.json",
+	// Git extension probes `.git/config` on every workspace folder to
+	// detect whether the folder is a git worktree; ENOENT is the
+	// normal "not a git repo" signal, not an error.
+	"/.git/config",
 	// Chat language-model registry is written on first chat interaction.
 	// Absent on fresh profiles; VS Code reads-before-first-write every boot.
 	"chatLanguageModels.json",

Source/Vine/Server/MountainVinegRPCService.rs

@@ -831,15 +831,25 @@ impl MountainService for MountainVinegRPCService {
 				// event that Wind may or may not listen for. The
 				// `notif-drop` tag surfaces every fall-through so we can
 				// tell at a glance which notifications Cocoon emits that
-				// Mountain has no first-class handler for (register_*
-				// provider variants beyond the seven handled above,
-				// register_debug_adapter, register_task_provider,
-				// register_uri_handler, register_file_system_provider, …).
+				// Mountain has no first-class handler for. The large OR
+				// match above covers every `register_*` / `register_*_provider`
+				// variant the Cocoon vscode-API shim is known to emit;
+				// anything reaching here is either a new upstream addition or
+				// an `unregister_*` / generic notification without a typed
+				// handler. Payload preview included so diagnosis doesn't need
+				// a second run.
+				let PayloadPreview = if NotificationData.parameter.len() <= 160 {
+					String::from_utf8_lossy(&NotificationData.parameter).into_owned()
+				} else {
+					let Slice = &NotificationData.parameter[..160];
+					format!("{}…", String::from_utf8_lossy(Slice))
+				};
 				dev_log!(
 					"notif-drop",
-					"[NotifDrop] method={} payload_bytes={} (falls through to cocoon:{} event)",
+					"[NotifDrop] method={} payload_bytes={} preview={:?} (falls through to cocoon:{} event)",
 					MethodName,
 					NotificationData.parameter.len(),
+					PayloadPreview,
 					MethodName
 				);
 				// Forward all unknown notifications as Tauri events so Wind