Add JSONC Support for Project, Meta, and Model JSON files (#1144)

Replaces `serde_json` parsing with `jsonc-parser` throughout the
codebase, enabling support for **comments** and **trailing commas** in
all JSON files including `.project.json`, `.model.json`, and
`.meta.json` files.
MSRV bumps from `1.83.0` to `1.88.0` in order to
use the jsonc_parser dependency.

src/lib.rs

@@ -10,6 +10,7 @@ mod tree_view;
 mod auth_cookie;
 mod change_processor;
 mod glob;
+mod json;
 mod lua_ast;
 mod message_queue;
 mod multimap;