fix: resolve 3 protocol bugs, improve CLI and snapshot code quality (#487)

## Summary

- Fix `allowFileAccess` being silently stripped from launch commands by adding it to the Zod schema in `protocol.ts` (the `--allow-file-access` CLI flag was not reaching the browser)
- Fix `trace stop` requiring a path argument despite help text documenting it as optional -- now works with or without a path
- Fix `addscript`/`addstyle` silently succeeding when neither `content` nor `url` is provided -- now returns a validation error
- Replace hardcoded ANSI escape code with `color::error_indicator()` in `main.rs` to respect `NO_COLOR`
- Fix double-parse pattern and add descriptive expect messages in `commands.rs`
- Fix incomplete string escaping in `snapshot.ts` `buildSelector` (use `JSON.stringify` instead of manual quote escaping)
- Simplify redundant ternary in `snapshot.ts` cursor-interactive role assignment
- Sync docs changelog with CHANGELOG.md (v0.8.1 through v0.10.0)

cli/src/output.rs

@@ -344,6 +344,11 @@ pub fn print_response(resp: &Response, json_mode: bool, action: Option<&str>) {
                 return;
             }
         }
+        // Trace stop without path
+        if data.get("traceStopped").is_some() {
+            println!("{} Trace stopped", color::success_indicator());
+            return;
+        }
         // Path-based operations (screenshot/pdf/trace/har/download/state/video)
         if let Some(path) = data.get("path").and_then(|v| v.as_str()) {
             match action.unwrap_or("") {