Finish CUST-WP-0011 and implement STATE-WP-0061 suggestion backlog.

Add persisted Suggestion entities with WSJF ranking, relevance bumps,
REST/MCP write surfaces, /suggestions dashboard page, and daily triage
digest integration. Document the cluster operating model, archive the
completed migration workplan, and seed WARDEN-WP-0012 routing scenarios.

api/services/suggestion_wsjf.py

@@ -0,0 +1,17 @@
+from __future__ import annotations
+
+from api.models.suggestion import Suggestion
+
+
+def cost_of_delay(suggestion: Suggestion) -> float:
+    return suggestion.base_value + (suggestion.relevance_weight * suggestion.relevance)
+
+
+def compute_wsjf(suggestion: Suggestion) -> float:
+    size = suggestion.job_size if suggestion.job_size > 0 else 3.0
+    return round(cost_of_delay(suggestion) / size, 2)
+
+
+def suggestion_sort_key(suggestion: Suggestion) -> tuple[float, int, str]:
+    """Higher WSJF first; tie-break on relevance then title."""
+    return (-compute_wsjf(suggestion), -suggestion.relevance, suggestion.title.lower())