Normalize CRLF; add English (en_version) support and language flags

[Cbphcr]

Motivation

• Reduce noisy diffs by restoring original CRLF endings for environment files that were unintentionally converted to LF.
• Add language support so dataset loading and environment tools can use English variants of data files and return English messages when requested.
• Make the environment and tooling configurable via a --lang flag to run experiments/evaluations in zh or en mode.
• Fix small API/behavior issues discovered while enabling language variants (string parsing, closed/open handling, and data mapping).

Description

• Restored CRLF line endings for: chinatravel/environment/world_env.py, chinatravel/environment/tools/attractions/apis.py, chinatravel/environment/tools/restaurants/apis.py, and chinatravel/environment/tools/poi/apis.py without changing logic.
• Added language handling in dataset loader: new helper functions _get_language and _normalize_query_language in chinatravel/data/load_datasets.py to swap language-specific fields (e.g. *_en) into base keys when lang == 'en'.
• Introduced en_version flags to the environment and tool classes (WorldEnv, Poi, Attractions, Accommodations, Restaurants, IntercityTransport, Transportation) and used a file_suffix = "_en" convention to load language-specific files when en_version=True.
• Propagated language selection through CLI and runtime: added --lang argument to run_exp.py, run_tpc.py, eval_exp.py, and eval_tpc.py, and pass en_version=args.lang == 'en' into WorldEnv construction.
• Improved IntercityTransport by keeping city name mappings (city_cn_to_en, city_en_to_cn) and accepting either Chinese or English city names in select.
• Made Poi.search return English or Chinese error messages based on en_version, and adjusted metro-station labeling in Transportation.goto to use English labels when en_version is enabled.
• Fixed Restaurants.id_is_open to treat both Chinese "不营业" and English "closed" as closed, and ensured hard_logic_py from the HF dataset is ast.literal_eval-parsed only when it's a string.
• Replaced several pop-based transfers with assignments to avoid mutating intermediate maps unnecessarily.
• Commit message: Normalize line endings for env files back to CRLF for the EOL normalization commit.

Testing

• Verified EOL differences are non-functional using git diff --ignore-cr-at-eol which showed no content changes for the normalized files (success).
• Ran python -m compileall on the touched environment files which completed without errors (success).
• Ran custom scripts to inspect and convert line endings (python one-liners used to count and rewrite EOLs) and validated the conversions (success).
• Confirmed repository status and made a commit with the normalization changes (commit recorded).

---

Codex Task