feat: comprehensive TNFR canonicalization and documentation unification

Documentation:
- Unified structural tetrad (Φ_s, |∇φ|, K_φ, ξ_C) documentation with single canonical sources
- STRUCTURAL_FIELDS_TETRAD.md as canonical definitions, U6_STRUCTURAL_FIELD_TETRAD.md for grammar
- AGENTS.md trimmed to reference canonical docs instead of duplicating formulas
- src/tnfr/physics/README.md enhanced as unified physics hub
- EXTENDED_FIELDS_INTEGRATION_SUMMARY.md now integration-status only
- Added OZ→IL precision walk telemetry references to physics module docs

Operators:
- Refactored operator implementations for cleaner architecture
- Enhanced grammar validation and memoization
- Updated operator registry with improved consistency
- Streamlined operator definitions removing redundant code

Fields & Physics:
- Optimized structural fields computation (fields.py ~1480 lines reduced)
- Enhanced canonical field implementations
- Improved precision mode handling

Tests & Benchmarks:
- Added precision walk dashboard artifact test
- Enhanced bifurcation landscape detection
- Updated critical exponent analysis tools
- Added tetrad telemetry benchmarks

Infrastructure:
- Updated Makefile with new smoke tests
- Enhanced CONTRIBUTING.md with language policy
- Expanded DOCUMENTATION_INDEX.md with precision walk references
- Added regression smoke test workflow

Author: fer

.github/workflows/regression-smoke.yml

@@ -0,0 +1,63 @@
+name: Regression Smoke (Bifurcation Tetrad)
+
+on:
+  pull_request:
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  smoke:
+    runs-on: ubuntu-latest
+    timeout-minutes: 15
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.10'
+
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install -e ".[dev-minimal]"
+
+      - name: Run bifurcation smoke sweep (with optional baseline compare)
+        run: |
+          set -e
+          mkdir -p results
+          BASELINE="presets/regression/bifurcation_smoke.baseline.jsonl"
+          if [ -f "$BASELINE" ]; then
+            echo "Using baseline: $BASELINE"
+            python tools/run_tetrad_regression.py \
+              --output results/bifurcation_smoke.jsonl \
+              --baseline "$BASELINE" \
+              --tolerance 5e-3 \
+              --nodes 150 \
+              --seeds 1 \
+              --topologies ring,ws \
+              --oz-intensity-grid 1.2 \
+              --vf-grid 1.0 \
+              --mutation-thresholds 1.3 | tee results/regression_summary.txt
+          else
+            echo "No baseline found; running smoke only"
+            python tools/run_tetrad_regression.py \
+              --output results/bifurcation_smoke.jsonl \
+              --nodes 150 \
+              --seeds 1 \
+              --topologies ring,ws \
+              --oz-intensity-grid 1.2 \
+              --vf-grid 1.0 \
+              --mutation-thresholds 1.3 | tee results/regression_summary.txt
+          fi
+
+      - name: Upload artifact (JSONL + summary)
+        uses: actions/upload-artifact@v4
+        with:
+          name: bifurcation-smoke-results
+          path: |
+            results/bifurcation_smoke.jsonl
+            results/regression_summary.txt