feat(example): add supply-chain-vsm composition demo (S3.5)

Demonstrates infospace composition: the Wealth of Nations infospace is
used as a discipline, applying Smith's economic framework as a lens to
analyse modern supply chain management concepts.

New example: examples/supply-chain-vsm/
- infospace.yaml binding WoN as discipline (../infospace-with-history)
- 3 source documents: coordination mechanisms, capital & inventory,
  market structure (~400 words each, original content)
- supply-chain-entity-schema-v1.0.md with WoN Concept required section
- won-mapping-schema-v1.0.md with Conceptual Continuity rating
- artifacts/won-reference/core-entities.md — 12 curated WoN entities
  for injection as discipline context
- 8 hand-crafted entity files demonstrating LLM output format
- 3 mapping files with full rationale and VSM inheritance chains
- Viable: YES (5/5 thresholds)

Key mappings demonstrated:
  Demand Signal          → Effectual Demand        (Strong, S2)
  Vendor-Managed Inventory → Division of Labour    (Strong, S1/S2)
  Just-in-Time Inventory → Circulating Capital     (Strong, S1/S3)
  Bullwhip Effect        → Natural Price           (Moderate, S2)
  Platform Intermediary  → Merchant Capital        (Strong, S2/S4)
  Monopsony Power        → Combination of Masters  (Strong, S3*)

Platform fix: entity_parser.py now recognises ## Supply Chain Domain
as a domain alias for ## Economic Domain, enabling composed infospaces
to use their own domain section name.

Tutorial §13 rewritten with real commands, real output, and the full
mapping table from the demo.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

examples/supply-chain-vsm/output/entities/demand-signal.md

@@ -0,0 +1,39 @@
+<!-- generated: provider=openrouter model=arcee-ai/trinity-large-preview:free date=2026-02-22 source=coordination-mechanisms -->
+
+# Demand Signal
+
+## Definition
+
+Information about consumer purchasing activity that propagates upstream
+through a supply chain to inform supplier replenishment and production
+decisions. A demand signal may be a point-of-sale data feed, a retailer's
+replenishment order, or a forecast. Signal quality — latency, accuracy,
+and granularity — determines how well upstream production can be
+synchronised with downstream consumption.
+
+## Source
+
+Coordination Mechanisms in Modern Supply Chains, §Demand Signals and
+Information Flow
+
+## Supply Chain Domain
+
+Coordination
+
+## VSM Assignment
+
+S2 — The demand signal is the primary coordination variable of the supply
+chain, analogous to the price signal in a market. It tells each upstream
+node what the downstream node requires, enabling synchronised response
+without central direction.
+
+## WoN Concept
+
+Effectual Demand — Smith's effectual demand — the demand of those willing
+and able to pay — is the signal that calls productive resources into action.
+The modern demand signal is effectual demand made explicit and machine-readable:
+instead of inferring demand from price movements, modern supply chains
+transmit demand data directly. Both serve the same coordination function
+(telling producers how much to produce), but where Smith's effectual demand
+works through price as a lagged, aggregated signal, the modern demand signal
+aims for real-time, granular transmission.