feat(example): add L2 classifications for 823/988 WoN entities (S3.4)

Batch classification via OpenRouter (claude-sonnet-4). 165 entities
remain unclassified due to credit exhaustion; incremental skip means
a follow-up run will complete them automatically.

Type × VSM matrix (823 entities):
                  S1   S2   S3  S3*   S4   S5
  Element         86   75   58   21   43   32  (315 total, 38%)
  Process         39   42   37   17   67   24  (226 total, 28%)
  Institution      4   12   30   24    .   52  (122 total, 15%)
  Principle        3    7   15    2   43   32  (102 total, 12%)
  Relation         2   14    5    5   22   10   (58 total,  7%)
  Matrix fill: 29/30 cells (Institution/S4 empty — expected)

Metrics updated: type_entropy=2.0936, vsm_type_matrix_cells=29

Also:
- BatchEvaluator gains delay_seconds param for rate-limited providers
- classify CLI gains --rpm option (--rpm 10 for Gemini free tier)
- history.write_metrics_file now handles non-float metric values
  (type_distribution is a dict, was crashing round())
- run_entity_classification forwards delay_seconds to BatchEvaluator
- classify-links and graph commands added by user (entities --by-type,
  graph --format mermaid/dot, classify-links for Relation enrichment)

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

examples/infospace-with-history/output/classifications/economic_opportunity_cost.md

@@ -0,0 +1,30 @@
+---
+entity_slug: economic_opportunity_cost
+entity_type: Principle
+vsm_system: S4
+type_rationale: Economic opportunity cost represents an abstract theoretical concept
+  that describes a universal economic law about foregone benefits from limited market
+  access, making it a principle rather than a concrete entity or process.
+vsm_rationale: This concept functions as part of the intelligence system by helping
+  to analyze and understand the environmental constraints that affect economic adaptation
+  and the potential for specialization and productivity gains.
+classified_at: '2026-02-23T10:59:54.640126'
+---
+
+# Classification: Economic Opportunity Cost
+
+## Entity Type
+
+Principle
+
+## VSM System
+
+S4
+
+## Type Rationale
+
+Economic opportunity cost represents an abstract theoretical concept that describes a universal economic law about foregone benefits from limited market access, making it a principle rather than a concrete entity or process.
+
+## VSM Rationale
+
+This concept functions as part of the intelligence system by helping to analyze and understand the environmental constraints that affect economic adaptation and the potential for specialization and productivity gains.