Frees v2/models/ to become the vendored-architecture namespace that mirrors fastvideo/models
(part of making v2 self-contained / able to replace fastvideo). The v2 recipe layer (per-family
card.py/loop.py/program.py + common.py + the build_*_engine re-exports) is the recipe, not the
architectures, so it moves to v2/recipes/. The pure-numpy toy/parity implementations (ToyDiT etc.)
move from v2/models/backend.py to v2/platform/backends/toy.py (alongside cpu.py/accel.py/torch_*).
Mechanical: all imports are absolute, so v2.models.<x> -> v2.recipes.<x> and v2.models.backend ->
v2.platform.backends.toy across v2/ + examples/ (89 files, 178 refs). No behavior change.
CPU mini green (202 passed, 2 skipped); all v2 files compile.
Addresses the 'how is ltx2 separate from ltx2.3' confusion + a wrong capability:
- LTX-2 cards renamed by ARCHITECTURE (the version labels did not map to it): build_ltx2_card model_id
'ltx2.3-distilled' -> 'ltx2-2stage-distilled' (two-stage base->upsample->refine; serves the
upsampler-having FastVideo/LTX2-Distilled-Diffusers); build_ltx2_base_card 'ltx2.base' ->
'ltx2-single-stage' (one loop; serves Davids048 base + the single-stage FastVideo/LTX-2.3-Distilled,
which has NO spatial_upsampler). Dispatch already splits on has_spatial_upsampler. Updated the
model-id refs in the mini's tests/examples.
- Wan2.1 base is T2V-only: dropped the wrong Capability.IMAGE_TO_VIDEO + narrowed components'
required_for to {t2v} (i2v is the separate InP variant; v2 has no i2v path yet). build_wan21_card is
shared by wan21 + wan2.2-ti2v; the A14B card was already T2V-only.
- CPU suite green (202 passed, 2 skipped).
Directory rename (git mv, history preserved) plus rewrite of all references: absolute imports in
tests, the zero-dep runner, docstrings, comments, and the README. No behavior change.
Run: python3 -m pytest v2/tests/ -q ; python3 v2/run_tests.py ; python3 -m v2.examples
Will Lin