feat: scaffold deployment-policies monorepo

OPA/Rego deployment gateway policies: 5 rules (valid-environment,
require-approvals, no-self-approval, block-weekends, freeze-window),
a deploy-gate combining them, JSON schemas, scenario-driven tests,
Gitea Actions CI (verify + publish to generic registry), changesets
versioning, Makefile and scripts.

policies/rules/block-weekends/package.json

@@ -0,0 +1,6 @@
+{
+  "name": "block-weekends",
+  "version": "0.0.0",
+  "description": "Denies deployments that fall on a weekend when the environment has block_weekends enabled.",
+  "private": true
+}

policies/rules/block-weekends/policy.rego

@@ -0,0 +1,21 @@
+# METADATA
+# schemas:
+#   - input: schema["input"]
+#   - data: schema["data"]
+
+package rules.block_weekends
+
+import rego.v1
+
+default allow := false
+
+allow if {
+	count(violations) == 0
+}
+
+violations contains {"code": "weekend_deploy", "message": sprintf("deployments blocked on %s for environment %q", [weekday, input.deployment.environment])} if {
+	input.deployment
+	weekday := time.weekday(time.parse_rfc3339_ns(input.deployment.created_at))
+	weekday in {"Saturday", "Sunday"}
+	data.deploygate.config[input.deployment.environment].block_weekends
+}

policies/rules/block-weekends/policy_test.rego

@@ -0,0 +1,12 @@
+package rules.block_weekends_test
+
+import data.rules.block_weekends as rule
+import rego.v1
+
+test_scenarios[scenario_name] if {
+	some scenario_name, scenario in data.scenarios
+	actual := {code | code := rule.violations[_].code} with input as scenario.input with data.deploygate as scenario.data
+	expected := {code | code := scenario.expect.violations[_]}
+	actual == expected
+	rule.allow == scenario.expect.allow with input as scenario.input with data.deploygate as scenario.data
+}

policies/rules/block-weekends/scenarios.json

@@ -0,0 +1,107 @@
+{
+  "scenarios": {
+    "weekday_ok": {
+      "input": {
+        "deployment": {
+          "environment": "production",
+          "service": "payments-api",
+          "version": "1.2.3",
+          "requested_by": "alice",
+          "created_at": "2026-09-15T10:00:00Z"
+        },
+        "approvals": []
+      },
+      "data": {
+        "config": {
+          "production": {"block_weekends": true}
+        }
+      },
+      "expect": {
+        "allow": true,
+        "violations": []
+      }
+    },
+    "saturday_blocked": {
+      "input": {
+        "deployment": {
+          "environment": "production",
+          "service": "payments-api",
+          "version": "1.2.3",
+          "requested_by": "alice",
+          "created_at": "2026-09-12T10:00:00Z"
+        },
+        "approvals": []
+      },
+      "data": {
+        "config": {
+          "production": {"block_weekends": true}
+        }
+      },
+      "expect": {
+        "allow": false,
+        "violations": ["weekend_deploy"]
+      }
+    },
+    "sunday_blocked": {
+      "input": {
+        "deployment": {
+          "environment": "production",
+          "service": "payments-api",
+          "version": "1.2.3",
+          "requested_by": "alice",
+          "created_at": "2026-09-13T10:00:00Z"
+        },
+        "approvals": []
+      },
+      "data": {
+        "config": {
+          "production": {"block_weekends": true}
+        }
+      },
+      "expect": {
+        "allow": false,
+        "violations": ["weekend_deploy"]
+      }
+    },
+    "weekend_not_blocked_when_disabled": {
+      "input": {
+        "deployment": {
+          "environment": "development",
+          "service": "payments-api",
+          "version": "1.2.3",
+          "requested_by": "alice",
+          "created_at": "2026-09-12T10:00:00Z"
+        },
+        "approvals": []
+      },
+      "data": {
+        "config": {
+          "development": {"block_weekends": false}
+        }
+      },
+      "expect": {
+        "allow": true,
+        "violations": []
+      }
+    },
+    "weekend_ignored_when_config_missing": {
+      "input": {
+        "deployment": {
+          "environment": "production",
+          "service": "payments-api",
+          "version": "1.2.3",
+          "requested_by": "alice",
+          "created_at": "2026-09-12T10:00:00Z"
+        },
+        "approvals": []
+      },
+      "data": {
+        "config": {}
+      },
+      "expect": {
+        "allow": true,
+        "violations": []
+      }
+    }
+  }
+}

policies/rules/block-weekends/schema/data.json

@@ -0,0 +1,27 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "type": "object",
+  "additionalProperties": true,
+  "properties": {
+    "deploygate": {
+      "type": "object",
+      "additionalProperties": true,
+      "properties": {
+        "config": {
+          "type": "object",
+          "additionalProperties": {
+            "type": "object",
+            "additionalProperties": true,
+            "properties": {
+              "block_weekends": {"type": "boolean"}
+            }
+          }
+        }
+      }
+    },
+    "rules": {
+      "type": "object",
+      "additionalProperties": true
+    }
+  }
+}

policies/rules/block-weekends/schema/input.json

@@ -0,0 +1,16 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "type": "object",
+  "additionalProperties": true,
+  "properties": {
+    "deployment": {
+      "type": "object",
+      "additionalProperties": true,
+      "required": ["environment", "created_at"],
+      "properties": {
+        "environment": {"type": "string"},
+        "created_at": {"type": "string", "format": "date-time"}
+      }
+    }
+  }
+}