Fix Redis Token Decoding for Zimfarm Authentication

[dkconnect]

So i was going through this file and I felt this is a big missing part here. Please have a look

Problem

1. Incorrect Token Lookup

• Redis returns data as "bytes" in many clients
• Code was accessing using "str" keys ("refresh_token")
• so the Result: token was never found

2.. Repeated Unnecessary Authentication Calls

• Because "refresh_token" was never detected, the system will continue requesting new tokens This will mean:
• Extra API calls
• Inefficient performance

3. Runtime Errors

• Direct ".decode()" could fail if Redis already returned strings

[kelson42]

@dkconnect Thank you for your PR. It will be reviewed by a maintainer within a few days.

[Copilot]

Pull request overview

This PR fixes Zimfarm authentication token retrieval by normalizing Redis hgetall() results so refresh tokens can be found even when Redis returns bytes, preventing unnecessary re-authentication.

Changes:

• Default Redis hash read to {} when missing to avoid None handling branches.
• Decode Redis hash keys/values from bytes to str before token lookup.
• Switch refresh-token presence check to key membership ("refresh_token" in data).

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[Copilot]

Now that Redis bytes keys/values are normalized, the code will start hitting the refresh path, but refresh_zimfarm_token() does not persist the refreshed token/expiry back to Redis. This means expires_time in Redis remains expired and get_zimfarm_token() will call the refresh endpoint on every invocation after expiry. Consider storing the refresh response (and updating expires_time if needed) so subsequent calls can reuse the cached access token.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.78%. Comparing base (7d01e46) to head (356d5a4).
⚠️ Report is 11 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1142   +/-   ##
=======================================
  Coverage   92.78%   92.78%           
=======================================
  Files          74       74           
  Lines        4311     4312    +1     
=======================================
+ Hits         4000     4001    +1     
  Misses        311      311           

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[dkconnect]

Hey @kelson42 @benoit74 I dont what am I missing here

do i need to do something different to pass the "Continuous Integration / black-format-check" test case

[audiodude]

Just run black . to format all files with black in place.

I will do a proper review soon.

[audiodude]

Preempted by #1146