feat(application): commands/queries + IChargeableCharConfigService (PRC-001)

src/api/SIGCM2.Application/Pricing/ChargeableChars/ChargeableCharSnapshot.cs

@@ -0,0 +1,10 @@
+namespace SIGCM2.Application.Pricing.ChargeableChars;
+
+/// <summary>
+/// PRC-001 — Lightweight value snapshot for the active chargeable-char config
+/// at the time of word counting. Used by IChargeableCharConfigService.
+/// Keyed by Symbol in the returned dictionary.
+/// </summary>
+public sealed record ChargeableCharSnapshot(
+    string Category,
+    decimal PricePerUnit);