docs: describe current behaviour in comments, drop internal references

[XieX]

Comment sweep for dev history and references to internal docs etc.

Comment/docstring-only, plus prose in packages/client/README.md. Every changed .py file was checked by parsing old and new with docstrings blanked: the ASTs match, so no code, runtime string or assertion message changed.

• Drop references to TESTING.md, §x.y section numbers and Appendix A.x (none of which exist in this repo). Section-header comments keep their descriptive names.
• Replace internal names: Gonfalon → LaunchDarkly / LaunchDarkly's cost attribution / the LLM Summary tab in LaunchDarkly; Jira keys (AIC-2948, AIC-2950, AIC-3230).
• Rewrite development-history narration ("used to", "previously", "predates this span work", "out of scope for this telemetry pass", "pre-span-era", bug stories in test docstrings) as statements of current behaviour, keeping the reasoning for why.
• README judge section: describe how all three judge paths build {{message_history}} today, rather than how they used to disagree.

References to TELEMETRY-CONTRACT.md are kept, since that file ships in this repo.

Not changed (runtime string): the assertion message at packages/langchain-agents/tests/test_handler.py:1512 still says (TESTING.md §1.2 Path C). TELEMETRY-CONTRACT.md itself also has some history narration (lines ~615, 647, 659, 674, 711), left for a follow-up.

Checks: uv run ruff check ., uv run ruff format --check ., uv run mypy packages/*/src, uv run pytest (1396 passed, 11 skipped).

🤖 Generated with Claude Code, updated by @XieX

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Note

Overview
This PR rewrites customer-facing comments, docstrings, and README prose across the Python AI SDK packages so they describe current behavior instead of internal development history, without changing runtime code (per the PR, ASTs match with docstrings blanked).

Documentation hygiene: Removes pointers to non-shipped internals such as TESTING.md, §x.y section labels, and Appendix A.x from test/module headers and section comments, while keeping descriptive section names. Replaces internal product names (e.g. Gonfalon → LaunchDarkly) and drops Jira ticket references in comments.

Tone and content: Converts “used to / pre-span / out of scope” narratives in handlers, utils, judges, and telemetry-related tests into present-tense invariants (why lazy SDK imports exist, why spans end in finally, judge message_history parity, semconv finish-reason mapping, etc.). TELEMETRY-CONTRACT.md references remain where that file ships with the repo.

README: The client README.md judge section now states that all judge paths include input and trajectory via JudgeTask, rather than describing past path disagreements.

Known leftover (not in this diff’s scope per description): one runtime assertion string in langchain-agents tests still mentions TESTING.md §1.2 Path C.

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