fix: respect --headed false flag in CLI (#757)

When user explicitly sets --headed false, the CLI was ignoring this
flag because the launch condition only checked if flags.headed was
true. This meant that --headed false would not trigger a launch
command, and subsequent commands would auto-launch with default
headless=true.

The fix adds a cli_headed flag to track when the user explicitly
sets --headed (regardless of value), and includes this in the
launch condition check.

Fixes #743

cli/src/commands.rs

@@ -2164,6 +2164,7 @@ mod tests {
             cli_annotate: false,
             cli_download_path: false,
             cli_native: false,
+            cli_headed: false,
             annotate: false,
             color_scheme: None,
             download_path: None,