Fix passlib/bcrypt incompatibility by switching to argon2

[Copilot]

passlib==1.7.4 is incompatible with bcrypt>=4.0.0, causing ValueError: password cannot be longer than 72 bytes on Python 3.12/Windows. Since passlib is effectively unmaintained at 1.7.4, switching to argon2 is the cleaner fix.

Changes

• requirements.txt: passlib[bcrypt]==1.7.4 → passlib[argon2]==1.7.4 (pulls in argon2-cffi)
• app/services/auth.py: CryptContext(schemes=["bcrypt"]) → CryptContext(schemes=["argon2"])
• .gitignore: Added root-level ignore for __pycache__/, *.db, .env, and other artifacts that were previously untracked

# before
pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")

# after
pwd_context = CryptContext(schemes=["argon2"], deprecated="auto")

Note: Existing bcrypt hashes in the database will no longer verify after this change. For this environment the DB is seeded fresh on each run, so there is no migration concern — but this should be considered before applying to any deployment with persistent user data.

Original prompt

Fix passlib/bcrypt compatibility issue on Windows with Python 3.12

The application fails with ValueError: password cannot be longer than 72 bytes when using passlib==1.7.4 with bcrypt==5.0.0 on Windows Python 3.12.

Root cause: Old passlib version (1.7.4) is incompatible with newer bcrypt (5.0.0). The passlib version in requirements.txt is outdated.

Solution: Update requirements.txt to use a newer passlib version that's compatible with bcrypt 5.0.0, or use argon2 instead of bcrypt for password hashing.

Recommended fix:

1. Update passlib to latest version in requirements.txt, OR
2. Change password hashing algorithm from bcrypt to argon2 which has better compatibility

This will resolve the Windows/Python 3.12 compatibility issue.

The following is the prior conversation context from the user's chat exploration (may be truncated):

Assistant: uvicorn is not installed. You need to install the dependencies from requirements.txt first.

Run this:

cd ~/customer-support-env
pip install -r requirements.txt

This will install uvicorn and all other required packages. After that, you can run:

uvicorn app.main:app --host 0.0.0.0 --port 7860

This pull request was created from Copilot chat.