Fix correspondent creation error by setting valid matching_algorithm value

[Copilot]

This PR fixes the error that occurs when paperless-gpt tries to create correspondents automatically. The issue was caused by sending an invalid matching_algorithm value to the paperless-ngx API.

Problem

When updating documents with suggested correspondents, users encountered this error:

Error creating correspondent: 400, {"matching_algorithm":["\"0\" is not a valid choice."]}

Root Cause

The instantiateCorrespondent function was setting MatchingAlgorithm: 0, but the paperless-ngx API only accepts specific values:

• 1: Auto (default matching)
• 2: Fuzzy matching
• 3: Regular expression
• 4: Exact match

Solution

Changed the MatchingAlgorithm field from 0 to 1 (Auto matching) in the instantiateCorrespondent function. This is a minimal, one-line fix that ensures compatibility with the paperless-ngx API while using the most appropriate default matching algorithm for automatically generated correspondents.

Testing

• Added comprehensive tests to verify the fix works correctly
• Validated that the JSON sent to paperless-ngx now contains "matching_algorithm": 1
• Confirmed existing functionality remains intact

Fixes #609.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• openaipublic.blob.core.windows.net
  • Triggering command: /tmp/go-build3221326226/b001/paperless-gpt.test -test.testlogfile=/tmp/go-build3221326226/b001/testlog.txt -test.paniconexit0 -test.timeout=10m0s -test.v=true (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

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