fix: tighten launch truthfulness and version probes

[RyshMan]

Problem

• launch and onboarding copy still described the OpenAI example as an official lane instead of a reference boundary demo
• release/install support flows needed a truthful version probe that survives tagged module installs without treating repo-local dev metadata as a release signal
• the new docs-site npm cache path dirtied the repo because /.cache/ was not ignored

Changes

• added CLI version resolution that prefers stamped releases, falls back to trusted Go build info for tagged installs, and preserves repo-local dev versions for checkout builds
• expanded install/release smoke coverage plus Python SDK tests so version aliases, delegation flags, trace helpers, and error paths are exercised
• updated README, docs, LLM docs, examples, issue templates, and integration guidance to distinguish the official LangChain lane from the OpenAI reference demo and to point automation at gait version --json
• ignored /.cache/ to keep the repo clean after docs-site validation targets

Validation

• ./gait doctor --json
• make prepush-full
• repo pre-push hook during git push -u origin codex/adhoc-launch-truthfulness

[chatgpt-codex-connector]

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