Fix Set Encoding + Field Names on Encoding Crashes

[hfern]

This fixes a bug where set-typed fields without default or specified values would crash on creation. This is because of an encoding bug: we passed in Unknown to the custom semantically_equal function implemented by Set. It was not expecting Unknown.

I went back and forth a couple of times on whether semantically_equal should be Unknown-aware or not. I am still not really sure. I ended up obviating the need to make a decision on that because the specific case that caused this had a broader solution: If the planned value was Unknown then we should just accept whatever the new value is. It can't be worse than Unknown.

I also added exception enrichment if this happens again and the provider framework catastrophically crashes. Now it will tell you specifically what field led to the exception.

[Copilot]

Pull Request Overview

This PR fixes a critical bug where set-typed fields without default or specified values would crash during resource creation due to an encoding issue where Unknown values were incorrectly passed to custom semantically_equal functions.

• Adds handling for Unknown planned values in the encoding logic to prevent crashes
• Introduces exception enrichment to provide better error messages when encoding failures occur
• Adds comprehensive test coverage for the bug scenario and error handling

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
tf/provider.py	Core fix for Unknown value handling and exception enrichment for encoding errors
tf/tests/test_provider.py	Test cases for the bug scenario and a custom Set type for testing
e2e/mathprovider/mathprovider/test_provider.py	Additional e2e test for for_each functionality
CHANGELOG.md	Documentation of the bug fix and new error reporting feature

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