LangChain tools normalized; zero sample rate preserved

What's Changed

• feat(api): update API spec from langfuse/langfuse b0387f7 by @langfuse-bot in https://github.com/langfuse/langfuse-python/pull/1770
• chore(deps): bump the github-actions group with 2 updates by @dependabot[bot] in https://github.com/langfuse/langfuse-python/pull/1773
• fix(langchain): normalize tool definitions to OpenAI function format by @milanagm in https://github.com/langfuse/langfuse-python/pull/1758
• chore(deps): bump the github-actions group with 2 updates by @dependabot[bot] in https://github.com/langfuse/langfuse-python/pull/1775
• chore(deps): bump actions/checkout from 7.0.0 to 7.0.1 in the github-actions group by @dependabot[bot] in https://github.com/langfuse/langfuse-python/pull/1780
• chore(deps): bump actions/setup-python from 6.3.0 to 7.0.0 in the github-actions group by @dependabot[bot] in https://github.com/langfuse/langfuse-python/pull/1783
• feat(api): update API spec from langfuse/langfuse a9f0808 by @langfuse-bot in https://github.com/langfuse/langfuse-python/pull/1778
• fix: preserve zero sample rate by @hassiebp in https://github.com/langfuse/langfuse-python/pull/1784
• chore(deps): bump the github-actions group with 3 updates by @dependabot[bot] in https://github.com/langfuse/langfuse-python/pull/1785
• fix(experiments): preserve run metadata precedence by @marliessophie in https://github.com/langfuse/langfuse-python/pull/1756
• fix(api): preserve legacy score create alias by @hassiebp in https://github.com/langfuse/langfuse-python/pull/1786
• fix(api): initialize compatibility exports safely by @hassiebp in https://github.com/langfuse/langfuse-python/pull/1789
• feat(api): update API spec from langfuse/langfuse 8242934 by @langfuse-bot in https://github.com/langfuse/langfuse-python/pull/1790
• chore(deps): bump the github-actions group with 2 updates by @dependabot[bot] in https://github.com/langfuse/langfuse-python/pull/1787
• chore(deps): bump zizmorcore/zizmor-action from 0.6.0 to 0.6.1 in the github-actions group by @dependabot[bot] in https://github.com/langfuse/langfuse-python/pull/1793
• fix(observe): defer span end when a cancellation never resumed the generator by @DavidTraina in https://github.com/langfuse/langfuse-python/pull/1792
• fix(ci): run Langfuse v4 in dual-write mode by @hassiebp in https://github.com/langfuse/langfuse-python/pull/1795

Full Changelog: https://github.com/langfuse/langfuse-python/compare/v4.14.1...v4.14.2