Permafrost 0.2.0 — installable Claude Code plugin

First marketplace release. Install inside Claude Code:

/plugin marketplace add jianzhichun/permafrost
/plugin install permafrost@permafrost

What it does: freezes Claude Code's prompt prefix so DeepSeek's automatic cache keeps hitting — measured 64% cost reduction on real Claude Code traffic (66% cache hit over a 4-turn agentic task), validated against the live api.deepseek.com/anthropic endpoint.

Highlights

• Alignment proxy: deterministic tool sort, cache_control strip, env freeze+delta, billing-nonce stabilization, canonical serialization
• Cold-anchor coalescing for parallel subagent fan-out (live: 0% → 73% hit)
• Opt-in idle keepalive (live: 99.9% hit on unchanged replay) + permafrost warm
• Per-session & per-lineage stats, /permafrost:status|doctor|benchmark|wrap commands, savings statusline
• Zero dependencies (stdlib Python); offline benchmark + isolated e2e harness (e2e/run_claude_code.sh)

Measured DeepSeek cache behavior (see docs/e2e-findings.md): the endpoint re-renders to canonical order before caching; cache identity includes request params and the client header fingerprint; partial-prefix (anchor-only) warms never hit.