bug(mcp): JSON-RPC 2.0 / MCP compliance gaps #336

crates/trapfall-mcp/src/lib.rs:15-39

• Notifications (no id, e.g. notifications/initialized) get a response with id: null; must get none.
• Wrong codes: unknown method -32603 (should be -32601), bad params -32603 (-32602), invalid request -32600.
• Batch arrays unsupported; jsonrpc != "2.0" not validated; initialize ignores client protocolVersion.
• tools/call failures should be isError: true content, not protocol errors.
• Blocking std stdin in async code; unwrap() at line 24; key slicing &new_key[..8] (lines ~402, 418-422) can panic on short/multibyte keys.

Strict MCP clients may break. Related: #215.