feat(3.x): align Comfy CLI/MCP and production hardening

[loong10k]

Aligns comfy-java-sdk with current Comfy CLI + local comfy-mcp.

Highlights:

• broaden documented CLI command coverage and keep raw escape hatch
• parse the global --json envelope
• make GenerateOptions copyable/non-mutating with validated routing
• use the dedicated probe timeout
• bound stdout/stderr capture to prevent heap growth
• harden MCP stdio lifecycle: drain stderr, bounded frame reads, remove pending RPCs on every terminal path, reject duplicate connect, deterministic process/thread/timer cleanup
• preserve all MCP content types and add typed convenience wrappers for the current local comfy-mcp tool surface
• regression tests for timeout cleanup, stderr backpressure, mixed content and resource cleanup

This is the Java 21 / Jackson 3 hardening line; equivalent business logic will be ported to 2.x and 1.x after this line is green.