v3.3.4

S-expression plan format, retry escalation, collapsible steps

• S-expr plan format: planCodeArchitecture() uses hybrid JSON+S-expression — :do and :proof fields encode tasks concisely with structural intent and acceptance criteria
• Retry escalation: failed Gemini Flash Lite chunks retry with gemini-2.5-flash before escalating to Kimi review
• Collapsible steps: completed pipeline steps collapse into expandable "N steps completed" summary
• Plan normalization: S-expr format auto-converts to legacy format for downstream compatibility