fix: add missing re.DOTALL flag to DeepSeek V3 tool call parser

[PercyDikec]

What does this PR do?

The DeepSeek V3 tool call parser regex was missing re.DOTALL, so .* couldn't match newlines in the function_arguments capture group. Since tool call JSON arguments are almost always multi-line, the parser silently failed on most real tool calls and returned raw text instead.

Every other parser in the codebase (hermes, mistral, glm45, glm47, qwen3_coder, kimi_k2, longcat) already uses re.DOTALL for their patterns.

Related Issue

Fixes #443

Type of Change

• Bug fix (non-breaking change that fixes an issue)

Changes Made

• environments/tool_call_parsers/deepseek_v3_parser.py: Added re.DOTALL flag to PATTERN regex compilation

How to Test

1. Check every other parser file in environments/tool_call_parsers/ - all use re.DOTALL
2. Without the flag, this regex only matches single-line JSON: {"query": "hello"}
3. With the flag, multi-line JSON is matched correctly:

{
  "query": "hello",
  "limit": 5
}

Checklist

Code

• I've read the Contributing Guide
• My commit messages follow Conventional Commits
• I searched for existing PRs to make sure this isn't a duplicate
• My PR contains only changes related to this fix
• I've tested on my platform: Ubuntu 24.04

Documentation & Housekeeping

• N/A (one flag added, no docs/config/schema changes)

[teknium1]

Merged in commit 936fda3 🎉 Thanks @PercyDikec!

Also found the same bug in deepseek_v3_1_parser.py — its regex also used .*? without re.DOTALL, so multi-line JSON arguments would fail there too. Fixed in follow-up commit dc55f49.