sim: consolidate to Tsimulation/{sim_v1,sim_v2}, retire v3 numbering

[ElmoPA]

Replaces the three-version pushshapes/{v1,v2,v3} fork from the parent branch
with two standalone sibling packages, each carrying its own pushshapes/,
collect/, examples/ and tests/.

There is no v3. What was labelled v3 is the socket fix that ships AS v2 -- the
intermediate all-faces-grip build was a bug, never a release -- so SIM_VERSION
goes 3 -> 2. Content is otherwise identical to the old v3: obstacles, render
and shapes differ by 0 lines. sim_v1 is unchanged physics (imports and a stale
banner only), which is why every v1 dataset still replays bit-exact.

Tsimulation/init.py aliases the active version submodules to the top level,
so existing "from Tsimulation.pushshapes import X" call sites keep working.
Version selection moves to TSIM_VERSION (default sim_v2) -- per-process and
visible in the job environment, unlike the old symlink.

Verified by replay against real data: 74,001 episodes across 25 datasets. v1
sets reproduce at 100%, v2 sets at 92-99%. Post-consolidation regression:
probe_indomain_circle_v1 100%, u_socket_3000_v2 96%.

Co-Authored-By: Claude Opus 5 (1M context) noreply@anthropic.com
Claude-Session: https://claude.ai/code/session_012V58H37tmcvgDthELMd5Xk

[ElmoPA]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• feat(robot): deploy graph policies on Python 3.10 #578
• feat(pipeline): sync current inference graph runtime #577
• feat(pipeline): sequential H-Net pipeline, flat stages instead of a nested trunk #567
• feat(rldb): heterogeneous u_socket action support #566
• refactor(config): organize all Hydra configs by family and task #551
• tsim: sim env + viz/scripts + physics tuning #549
• sim: consolidate to Tsimulation/{sim_v1,sim_v2}, retire v3 numbering #546 👈 (View in Graphite)
• sim: fork PushShapes into frozen per-version packages (v1/v2/v3) #542
• feat(rldb): h264 video-backed images + role-in-key annotations + span selection #541 : 1 other dependent PR (#550 )
• TTT-Linear across-time layer (RoboTTT-style): closed-form inner SGD on fast weights, per-episode reset, tanh-gated ~identity at init; DualTrunkLevel ttt knob; arms fix2ada+ttt (H-Net) and txar_sdpada(+ttt) flat pair #540
• main

This stack of pull requests is managed by Graphite. Learn more about stacking.