v0.4.0 — Design Generation Engine + Infrastructure Reliability

Design Generation (10 improvement loops)

• Geometry-aware reasoning engine — structural analysis beyond lookup tables (overhang detection, thin walls, support estimation, load paths)
• Compositional generation — build functional parts from primitives + boolean CSG operations
• Auto-reinforcement — structural analysis → automatic reinforcement application
• Slicer profile inference — structural properties → optimal slicer settings
• Smart template pipeline — NL description → template match → OpenSCAD → STL in one call
• Expanded primitive DSL — 70 parametric templates across 13 categories (was 21)
• 6 new MCP tools: search_design_templates, estimate_mesh_weight, design_to_gcode_pipeline, merge_stl, cross_section_view, solve_template_constraints
• 404 MCP tools total (was 395)

Infrastructure Reliability

• cancel_at_percent — watch_print auto-cancels at a configurable progress threshold (no more agent polling scripts)
• Camera ground-truth — MD5 hash comparison of consecutive snapshots detects telemetry mismatch (progress stuck but camera shows movement)
• Tri-state AMS auto-detect — use_ams="auto" probes printer for loaded AMS trays, auto-enables and auto-maps filament slots

Housekeeping

• Ruff lint cleanup across 95 test files
• Input validation before OpenSCAD discovery in boolean/compose operations
• 7,936 tests (was 7,621)