feat: enhance sorter simulation demo

docs/DEMO_SCRIPT.md

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+# Demo Script
+
+Target duration: 3-5 minutes.
+
+## 1. Open The Dashboard
+
+Open https://arhipovdan.ru/.
+
+Explain that this is a 2D engineering simulation, not a decorative animation: the SVG scene shows a scaled work zone, conveyor dimensions, sensors, stop-gate, pushers and roll-cages.
+
+## 2. Normal Flow
+
+Select `Normal flow`, press `Start`.
+
+Explain:
+
+- item enters zone A;
+- camera captures bbox;
+- laser measures height;
+- ultrasonic confirms gate position;
+- gate holds item;
+- classifier selects B/C/D;
+- route command is shown on the scene;
+- event log records the full cycle.
+
+Question closed: can the system show a full sorting cycle end-to-end?
+
+## 3. Step-By-Step Decision
+
+Press `Reset`, then use `Step state`.
+
+Explain each state in the timeline. Show that Step advances by logical state, not by arbitrary animation time.
+
+Question closed: can the jury inspect synchronization and state transitions?
+
+## 4. Oversized And Round Rules
+
+Select `Oversized item`, step to classification.
+
+Show decision tree:
+
+- dimensions check fails;
+- category C selected;
+- roundness is lower priority because dimensions are checked first.
+
+Then select `Round object` and show D when dimensions pass and roundness >= 0.8.
+
+Question closed: how is classification proved?
+
+## 5. Robustness Scenarios
+
+Show `close_items`, `low_confidence`, `jam`, `emergency_stop`.
+
+Explain:
+
+- close items generate spacing warning and queue length;
+- low confidence uses rule-based fallback;
+- jam enters FAULT and stops conveyor;
+- emergency stop enters EMERGENCY_STOP and requires Reset.
+
+Question closed: what happens outside the happy path?
+
+## 6. PID And Metrics
+
+Point to PID panel and metrics cards.
+
+Explain that PID is simplified: actual speed approaches target in normal flow and decays toward zero in fault/emergency.
+
+Question closed: how is conveyor control represented without overbuilding physics?