feat(integration): bind plugin operator authority to exact request

apps/integration-service/migrations/0003_plugin_operator_context_replay_record.sql

@@ -0,0 +1,19 @@
+CREATE TABLE plugin_integration.plugin_operator_context_replay_record (
+    evidence_id uuid PRIMARY KEY,
+    consumed_at timestamptz NOT NULL,
+    expires_at timestamptz NOT NULL,
+    CONSTRAINT plugin_operator_context_replay_lifetime_check
+        CHECK (expires_at >= consumed_at)
+);
+
+CREATE INDEX plugin_operator_context_replay_expiry_index
+    ON plugin_integration.plugin_operator_context_replay_record (expires_at);
+
+COMMENT ON TABLE plugin_integration.plugin_operator_context_replay_record IS
+    'Durable one-time plugin operator evidence consumed by the Integration service to prevent replay across service instances.';
+COMMENT ON COLUMN plugin_integration.plugin_operator_context_replay_record.evidence_id IS
+    'Signed UUIDv4 evidence identity; primary-key uniqueness permits exactly one durable consumption.';
+COMMENT ON COLUMN plugin_integration.plugin_operator_context_replay_record.consumed_at IS
+    'Instant when the winning Integration service instance consumed the signed evidence.';
+COMMENT ON COLUMN plugin_integration.plugin_operator_context_replay_record.expires_at IS
+    'Retention deadline after which the evidence record is eligible for cleanup because its signature lifetime has closed.';