Feature/token limit reached exception

[saarnilauri]

This PR adds explicit token-limit handling for Anthropic so truncated outputs are surfaced as exceptions instead of normal results.

What changed

• Added TokenLimitReachedException (src/Common/Exception/TokenLimitReachedException.php) with structured metadata:

  • maxTokens
  • providerStopReason
  • optional functionName
  • optional missingRequiredParameters

• Updated Anthropic response parsing (src/ProviderImplementations/Anthropic/AnthropicTextGenerationModel.php) to throw TokenLimitReachedException when stop_reason is:

  • max_tokens
  • model_context_window_exceeded

• Added tool-call diagnostics for partial argument payloads by comparing returned args with required schema fields.

• Added Anthropic unit test scaffolding and initial coverage:

  • tests/unit/ProviderImplementations/Anthropic/MockAnthropicTextGenerationModel.php
  • tests/unit/ProviderImplementations/Anthropic/AnthropicTextGenerationModelTest.php

• Added Anthropic integration tests for max-token scenarios (plain text + tool-calling):

  • tests/integration/Anthropic/TextGenerationIntegrationTest.php
  • tests/integration/Anthropic/FunctionCallingIntegrationTest.php

  This relates to Missing Required Parameters in Tool Calls When Token Limit Reached #193

I know that the providers will be moved to their own repositories. But as this change is still in very early stage. I decided to do this PR to the client repository, so that discussion on how this should be implemented can start.

The PR is co-authored with OpenAIs Codex 5.3 model.

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Co-authored-by: saarnilauri <laurisaarni@git.wordpress.org>

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