release: 0.22.0 — live MCP reconnect (identity + append)

[esengine]

Release commit for 0.22.0. Bumps package.json and adds the corresponding CHANGELOG.md entry. No code-path changes here — those landed in #112, #113, #114, #115, #116, #117, #118.

Highlights

• /mcp reconnect <name> — re-handshake the named server's transport, swap the underlying McpClient through a new mutable McpClientHost indirection. Identity-drift always accepted; append-drift accepted mid-session via applyMcpAppend (registers new tools + addTool the prefix). Edit / reorder / remove still refused with a clear "restart Reasonix to apply" message — they're catastrophic for cache.
• r / d keybinds in the /mcp browser modal route through the same shared helpers (kickOffMcpReconnect / toggleMcpDisabled) — modal and slash command behave byte-identically.
• Empirical-spike-driven design — benchmarks/spike-mcp-reconnect/ captures live deepseek-chat measurements showing the cache is chunk-keyed (~128 tokens). Append-drift retains 94.8% hit; first-tool description edit still retains 84.1%. Overturned the original RFC's "any drift = full miss" framing.

After merge

• Tag v0.22.0 on the squash-merge commit
• Push tag
• npm publish (after explicit confirmation — public/irreversible)