build(deps): bump blueprint_parser_creator deps (python-dotenv, loguru, regex, langchain-community, pytest)

[amirfz]

Summary

Supersedes #521, #522, #524, #527, #529 — folded into one branch since they're all independent single-line bumps to the same requirements.txt.

Package	From	To	PR
python-dotenv	>=1.0.0	>=1.2.2	#521
loguru	>=0.7.0	>=0.7.3	#522
langchain-community	>=0.0.10	>=0.4.2	#524
regex	>=2023.0.0	>=2026.7.19	#527
pytest	>=7.0.0	>=9.1.1	#529

Real bug found and fixed

This demo has its own test suite, but CI never runs it — the earlier PRs only had CI's "does it install" check to go on. Running the tests for real (with the bumped versions actually installed, not mocked) surfaced a genuine break: langchain_community.chat_models.ChatOpenAI no longer exists on current langchain-community. This isn't new from this bump — the >= pins here always resolve to latest, so it was already broken before today. Fixed both main.py and blueprint_utils.py to import ChatOpenAI from langchain_openai (the actively maintained package) instead, and added langchain-openai explicitly to requirements.txt since the code imports it directly.

Two pre-existing test failures are unrelated to any of this and left alone (out of scope): test_imports requires CLOUDCONVERT_API_KEY to be set in the environment, and test_environment_variables checks tests/.env-sample instead of the real .env-sample at the demo root.

Test plan

• Fresh venv, pip install -r requirements.txt with all 5 bumped versions resolved
• pytest tests/ — 11 passed, 2 pre-existing failures (unrelated, documented above)
• Confirmed the ChatOpenAI import break reproduces even without the version bump (latent, not introduced by this PR)
• CI on this PR

Co-Authored-By: Claude Sonnet 5 noreply@anthropic.com