chore: bump pytorch_connectomics to latest upstream and align backend with v2 CLI

[akgohain]

Summary

• Bumps pytorch_connectomics submodule to latest upstream (PytorchConnectomics/pytorch_connectomics), commit 0a0dceb8.
• Updates bootstrap/setup scripts to use the new repo owner URL and new pinned commit.
• Renames root dependency from connectomics to pytorch-connectomics in pyproject.toml to match upstream package metadata.
• Regenerates uv.lock for the new dependency graph.
• Adapts backend PyTC invocation to new CLI:
  • training/inference now launch with --config <temp.yaml> --mode train|test
  • removes deprecated --config-file / --inference usage
  • returns inference start metadata (status, pid)
  • hardens stop behavior so stopping training does not terminate inference.
• Updates preset and architecture endpoints for new upstream layout:
  • config presets discovered from pytorch_connectomics/tutorials (and configs fallback)
  • architectures resolved via connectomics.models.arch registry (with source fallback parsing).

Validation

• uv sync --frozen --python 3.11 passes.
• python -m compileall passes for changed backend files.
• Live smoke checks pass:
  • server_api and server_pytc boot and health endpoints respond.
  • /pytc/configs, /pytc/config, and /pytc/architectures return valid data.
  • /start_model_training and /start_model_inference succeed via both worker and API proxy paths.
  • worker logs show no unrecognized arguments CLI errors.

Scope Note

• This PR does not change frontend inference wiring; it is focused on dependency bump and backend compatibility with upstream PyTC changes.