feat: modernize PSO and add convergence research

Migrate the package and examples to the tensor-native PyTorch implementation, add benchmark evidence, and add the guarded post-training convergence protocol with TensorBoard progress monitoring and hash-verified recovery.

Constraint: Preserve one-shot official-test sealing and auditable research artifacts

Rejected: Commit local .omc runs and downloaded datasets | multi-gigabyte runtime state is machine-local

Confidence: high

Scope-risk: broad

Not-tested: Production CUDA run on pieroot-server

.github/workflows/python-package.yml

@@ -0,0 +1,41 @@
+name: Python package test
+
+on:
+  push:
+    paths:
+      - "pso/**"
+      - "pyproject.toml"
+      - "uv.lock"
+      - ".python-version"
+      - "README.md"
+      - "tests/**"
+      - ".github/workflows/python-package.yml"
+  pull_request:
+    paths:
+      - "pso/**"
+      - "pyproject.toml"
+      - "uv.lock"
+      - ".python-version"
+      - "README.md"
+      - "tests/**"
+      - ".github/workflows/python-package.yml"
+
+jobs:
+  test:
+    runs-on: ubuntu-22.04
+    strategy:
+      matrix:
+        python-version: ["3.10", "3.11"]
+
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install uv and Python ${{ matrix.python-version }}
+        uses: astral-sh/setup-uv@v9
+        with:
+          version: "0.12.7"
+          python-version: ${{ matrix.python-version }}
+          enable-cache: true
+      - name: Sync dependencies
+        run: uv sync --locked --group dev
+      - name: Run tests
+        run: uv run --no-sync pytest -q