docs: doc/ — the module map, the QC gates, and the agent tools

[ZheningHuang]

Somewhere to write down what the pipeline is made of and what each QC gate actually promises, rather than leaving it spread across module docstrings.

file	what it covers
doc/modules.md	the ten modules the system is built from, and the rule that every update ties to one
doc/QC/collision_check.md	entities, rules, the deterministic function, what a failure hands the repair step
doc/QC/supporting_relationship.md	the other half of sim-readiness — every object rests on something, and stays there
doc/Tools/threed_gen.md	the procedural / TRELLIS split and the router that chooses per object
doc/Tools/rendering_and_compare.md	render | photo pairing, the three target layers, and the two honest-render invariants
doc/Tools/image_selection.md	select_views — which frames a tool looks at, and why the agent never guesses one
doc/Tools/fetch_material.md	Poly Haven fetch + LAB recolour, and why the search ranking is fussier than it looks
doc/Sim-Ready-intergration/	metadata notes; MuJoCo still to write

What these pages are for

Each one records the parts that are decisions rather than implementation details — the things a reader cannot recover from the code:

• collision_check.md — which findings fail the gate and which don't (floating and outside_room are reported but never fail: one means a missing support object, the other means the scan's wall loop is wrong, and neither is repairable here); why contact comes from the raw triangles but distance from a convex decomposition; and that a failure hands the fixer an exact metric vector, not a description.
• supporting_relationship.md — that touching is not the same as supported. A lamp on the last centimetre of a table corner passes any gap test and topples on frame 1, so the check is contact plus centre-of-mass over the shared footprint. no_supporter only reports, because this stage can move an object but cannot invent the table that should have been under it.
• rendering_and_compare.md — the two invariants that keep a render honest: recompile when Room.py is stale, and repack any procedural object whose object.py is newer than its packed GLB. Without the second, editing an object and re-rendering shows the old one, and the agent concludes its edit did nothing.

Figures

assets/doc/ carries the per-tool figures from the project blog post, plus two stills from its object-reconstruction videos showing the same three panels down each route — procedural/articulated and TRELLIS. Provenance is recorded in assets/doc/README.md.

Also here

example-scans had been committed as a mode-160000 gitlink with no .gitmodules, so a fresh clone got an empty, unfixable directory. Untracked and ignored — the scans are cloned separately.

Still open

• doc/Sim-Ready-intergration/Mujoco.md is empty.
• collision_check.md says wall fixtures are "fixed to the wall". In the current code they are in no collision body at all — Panda-1 has five that are simply absent from the model.