refactor(workspace): enforce layered crate boundaries

crates/aether-provider/pool/src/capability.rs

@@ -0,0 +1,23 @@
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum ProviderPoolCapability {
+    PlanTier,
+    QuotaReset,
+    QuotaRefresh,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
+pub struct ProviderPoolCapabilities {
+    pub plan_tier: bool,
+    pub quota_reset: bool,
+    pub quota_refresh: bool,
+}
+
+impl ProviderPoolCapabilities {
+    pub fn supports(self, capability: ProviderPoolCapability) -> bool {
+        match capability {
+            ProviderPoolCapability::PlanTier => self.plan_tier,
+            ProviderPoolCapability::QuotaReset => self.quota_reset,
+            ProviderPoolCapability::QuotaRefresh => self.quota_refresh,
+        }
+    }
+}