docs: add real CLI E2E scenario corpus

[bingran-you]

Summary

• add a live-observed black-box E2E scenario corpus for real Claude Code CLI behavior
• index the new corpus from the verification-and-native-test-oracles node
• link the framework overview to the live CLI corpus so snapshot-derived and runtime-derived oracles stay connected

Validation

• exercised the local Claude Code CLI across interactive startup, headless print, JSON/schema output, session resume/continue/fork, stream-json, and doctor flows
• git diff --check
• first-tree verify could not be run on this machine because the first-tree executable is not installed

Notes

• the corpus explicitly separates hard assertions from drift-sensitive observations such as auto-update version changes and current --add-dir ambiguity
• the branch is a single docs commit and is intended to merge cleanly via squash