fix(cloud-tools): add defer free for stdout allocation (#173)

Add defer std.heap.page_allocator.free(stdout) after readToEndAlloc
to fix memory leak in runTriCloud() function that occurred on every
MCP tool call.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: Trinity Agent

tools/mcp/trinity_mcp/cloud_tools.zig

@@ -70,6 +70,7 @@ fn runTriCloud(buf: *[MAX_OUTPUT]u8, args: []const []const u8) []const u8 {
     const stdout = child.stdout.?.readToEndAlloc(std.heap.page_allocator, MAX_OUTPUT) catch {
         return copyToBuf(buf, "Error: Failed to read output");
     };
+    defer std.heap.page_allocator.free(stdout);
 
     _ = child.wait() catch {};