docs: capture non-persistent run cache oracle

[bingran-you]

Summary

• record that --no-session-persistence only blocks local session save and later continuation
• preserve the observed real-CLI nuance that provider-side prompt cache warming can still shift usage from cache-create to cache-read across independent runs

Verification

• node ../../first-tree/dist/cli.js verify
• ~/.local/bin/claude --session-id 11111111-1111-4111-8111-111111111111 -p "Reply with exactly OK" --output-format json --no-session-persistence