fix: warn on yaml list markers in claude args

[seshxn]

Summary

• warn when claude_args contains '-' YAML list markers inside an accumulated flag value
• ignore those marker tokens so they are not passed as allowed tools
• add parser coverage for the multiline allowed-tools mistake from Feature Request: Display syntax errors for .claude/setting.json and GitHub Actions workflows #242

Part of #242. This intentionally avoids the settings JSON parsing path because #1273 already covers that area.

Testing

• bun test ./test/parse-sdk-options.test.ts
• bun test
• bun run typecheck
• bun run format:check
• git diff --check