fix(example): skip prompt writes when output exists, add quality rubrics

INFRA-TASKS #5 — process_chapters.py now skips writing *-prompt.md files
when the corresponding output file already exists on disk. DB-only rebuilds
no longer dirty the working tree with unchanged prompt content.

INFRA-TASKS #8 — Added '## Quality Metrics' section to the entity and VSM
mapping schemas, defining the five evaluation dimensions (Definition Precision,
Source Grounding, Domain Placement, VSM Relevance, Explanatory Value) with
1–5 rubrics used by the evaluate-entity template.

Also updated INFRA-TASKS.md to reflect current resolution status for tasks
4–19 across S2 and S3.

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

examples/infospace-with-history/schemas/vsm-mapping-schema-v1.0.md

@@ -33,6 +33,25 @@ might not fit the VSM concept perfectly.
 Other VSM concepts this entity could plausibly map to,
 with brief rationale for each alternative.
 
+## Quality Metrics
+
+Used by the `evaluate-entity` prompt template when assessing mapping quality.
+Each dimension is scored 1–5, where 1 = very poor and 5 = excellent.
+
+### Rationale Rigour (1-5)
+Is the mapping justified with reference to Beer's VSM definitions, not just
+surface-level analogy? A score of 5 means the rationale cites specific VSM
+properties (e.g., "S2 attenuates variety between S1 units") and shows how
+the economic entity fulfils that role. A score of 1 means the rationale is
+a loose metaphor with no structural grounding.
+
+### Strength Calibration (1-5)
+Is the declared Mapping Strength (Strong, Moderate, Weak) consistent with
+the rationale given? A score of 5 means the declared strength matches the
+depth of correspondence described. A score of 1 means the strength is
+overclaimed (e.g., "Strong" for a tangential analogy) or underclaimed
+(e.g., "Weak" for a direct structural match).
+
 ## Validation Rules
 
 1. The document MUST contain an H1 heading in the format "Entity Name -> VSM Concept Name".