Gemini CLI nightly 20260801: capacity-exhaustion retry hang fix

Nightly build with two core fixes: capacity exhaustion is now classified as a terminal error so the CLI stops retrying and hanging, and InvalidStreamError details are propagated to the UI to explain empty responses.

Tool: gemini-cli · Version: v0.55.0-nightly.20260801.gf47d6c6f7 · Significance: 2/5 · fix