feat(otlp-transformer): add custom logs response deserializer

[pichlermarc]

Which problem is this PR solving?

Follow-up to #6390; replaces protobuf.js in logs response deserialization with a custom implementation.
Also removes generated code for OTLP logs from the published package, since we don't need it anymore.

The goal of this PR is not to improve performance but to fix:

• use of eval is strongly discouraged #4987 (having custom serializer/deserializers for each signal will solve this as we can remove the production dependency on protobuf.js)

Once this is merged, we can also go ahead an migrate the other signals away from protobuf.js, following the patterns from this PR and #6390; in the last PR, we should remove protobuf.js as a production dependency and move it to devDependencies instead. Once this is done #4987 should be fixed.

Disclosure of AI use: I used GitHub copilot with Claude Sonnet 4.6 to help with implementation.

Type of change

• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

• Existing unit tests
• Added unit tests

[codecov]

Codecov Report

❌ Patch coverage is 97.84946% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 95.75%. Comparing base (1cf5ef3) to head (b80fc89).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
...transformer/src/common/protobuf/protobuf-reader.ts	96.07%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6530      +/-   ##
==========================================
+ Coverage   95.74%   95.75%   +0.01%     
==========================================
  Files         371      373       +2     
  Lines       12514    12604      +90     
  Branches     2962     2982      +20     
==========================================
+ Hits        11981    12069      +88     
- Misses        533      535       +2     

Files with missing lines	Coverage Δ
...ackages/otlp-transformer/src/logs/protobuf/logs.ts	100.00% <100.00%> (ø)
...sformer/src/logs/protobuf/response-deserializer.ts	100.00% <100.00%> (ø)
...transformer/src/common/protobuf/protobuf-reader.ts	96.07% <96.07%> (ø)

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[trentm]

I think this looks good. I haven't hammered it with testing.

[trentm]

And almost 1MiB of JS just left the process.
... or almost (need trace and metrics as well).

[trentm]

Guessing the merge conflict is because I separately moved the changelog entry for the earlier change up to the top, not noticing that you were doing so here.