[codex] Add landmark ComponentPlan probe samples

[madawei2699]

Summary

• add six landmark-style ComponentPlan examples to the MinePilot examples gallery
• cover Taj Mahal, Eiffel Tower, Great Wall, Giza Pyramid, Colosseum, and Tower Bridge massing studies
• document the landmark probe results and current CraftDAG expression boundaries

Why

Before implementing MinePilot #15, this probes whether a model-like author can reduce large landmark prompts into bounded ComponentPlan outputs that CraftDAG can validate, compile, preview, and export.

The result suggests #15 is feasible if the model is prompted to generate simplified Minecraft-style massing studies rather than exact replicas.

Validation

• corepack pnpm build
• corepack pnpm lint
• runtime validation of all ComponentPlan samples with expandComponentPlan and compileComponentPlan
  • validated=21
  • totalBlocks=34333

Local Preview

• /examples, search landmark
• /playground?sample=taj-mahal-study
• /playground?sample=eiffel-tower-study
• /playground?sample=great-wall-study
• /playground?sample=giza-pyramid-study
• /playground?sample=colosseum-study
• /playground?sample=tower-bridge-study

[gemini-code-assist]

Code Review

This pull request documents a probe evaluating the expressiveness of CraftDAG ComponentPlan for model-assisted workflows and adds six landmark massing study samples (Taj Mahal, Eiffel Tower, Great Wall, Giza Pyramid, Colosseum, and Tower Bridge) to the sample utilities. The review feedback highlights several structural and alignment issues in the new samples, including vertical stacking overlaps in the Eiffel Tower study, mismatched foundation and tower footprints in the Tower Bridge study, and asymmetric gallery openings in the Colosseum study.

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[gemini-code-assist]

In the Eiffel Tower study, there are vertical stacking overlaps between components. Specifically, mid_tower (height 15, Y: 22..37) overlaps with upper_tower (starts at Y: 36) and middle_deck (Y: 34..36). Additionally, upper_tower (height 10, Y: 36..46) overlaps with top_cap (Y: 45..46). Adjusting the heights of mid_tower to 12 and upper_tower to 9 resolves these overlaps and perfectly aligns the total height with the 50-block height bounds.

        { id: "mid_tower", type: "SupportPost", inputs: [{ ref: "lower_deck" }], placement: { anchor: { x: 14, y: 22, z: 14 }, size: { width: 7, height: 12, length: 7 } }, materials: { main: "trim" } },
        { id: "middle_deck", type: "Platform", inputs: [{ ref: "mid_tower" }], placement: { anchor: { x: 11, y: 34, z: 11 }, size: { width: 13, height: 2, length: 13 } }, materials: { main: "floor" } },
        { id: "upper_tower", type: "SupportPost", inputs: [{ ref: "middle_deck" }], placement: { anchor: { x: 16, y: 36, z: 16 }, size: { width: 3, height: 9, length: 3 } }, materials: { main: "trim" } },
        { id: "top_cap", type: "Platform", inputs: [{ ref: "upper_tower" }], placement: { anchor: { x: 14, y: 45, z: 14 }, size: { width: 7, height: 1, length: 7 } }, materials: { main: "floor" } },
        { id: "spire", type: "SupportPost", inputs: [{ ref: "top_cap" }], placement: { anchor: { x: 17, y: 46, z: 17 }, size: { width: 1, height: 4, length: 1 } }, materials: { main: "roof" } }

[gemini-code-assist]

The foundations (left_pier and right_pier) have a length of 8 (Z: 5..13), whereas the towers they support (left_tower and right_tower) have a length of 10 (Z: 4..14). This causes the towers to overhang their foundations in the Z direction. Adjusting the piers' Z anchor to 4 and length to 10 ensures they perfectly match the towers' footprint.

        { id: "left_pier", type: "Foundation", placement: { anchor: { x: 5, y: 0, z: 4 }, size: { width: 10, height: 3, length: 10 } } },
        { id: "right_pier", type: "Foundation", placement: { anchor: { x: 37, y: 0, z: 4 }, size: { width: 10, height: 3, length: 10 } } }

[gemini-code-assist]

The left_gallery and right_gallery openings are placed with an offset of 7 on a wall of length 24, which makes them asymmetric (closer to the front than the back). Changing the offset to 9 centers them perfectly on the side walls, matching the symmetric design of the Colosseum.

Suggested change

	{ id: "left_gallery", type: "Opening", placement: { target: "outer_wall", wall: "left", offset: 7, y: 1, width: 5, height: 4 } },
	{ id: "right_gallery", type: "Opening", placement: { target: "outer_wall", wall: "right", offset: 7, y: 1, width: 5, height: 4 } }
	{ id: "left_gallery", type: "Opening", placement: { target: "outer_wall", wall: "left", offset: 9, y: 1, width: 5, height: 4 } },
	{ id: "right_gallery", type: "Opening", placement: { target: "outer_wall", wall: "right", offset: 9, y: 1, width: 5, height: 4 } }