P3.5: Add values.schema.json constraint for replicas>1 requires Redis

- Create charts/miroir/ with values.schema.json, values.yaml, Chart.yaml
- Add JSON Schema if/then constraint: replicas > 1 requires taskStore.backend=redis
- Include errorMessage for clear operator feedback when constraint is violated
- Add test cases in charts/miroir/tests/ for validation:
  * valid-single-replica-sqlite.yaml (replicas: 1, backend: sqlite) → pass
  * invalid-multi-replica-sqlite.yaml (replicas: 2, backend: sqlite) → fail
  * valid-multi-replica-redis.yaml (replicas: 2, backend: redis) → pass

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

charts/miroir/Chart.yaml

@@ -0,0 +1,6 @@
+apiVersion: v2
+name: miroir
+description: Distributed search orchestrator for Meilisearch
+type: application
+version: 0.1.0
+appVersion: "0.1.0"

charts/miroir/tests/README.md

@@ -0,0 +1,26 @@
+# Helm Chart Tests
+
+This directory contains test cases for validating the `values.schema.json` constraints.
+
+## Running Tests
+
+Use `helm lint --strict` with the test values files:
+
+```bash
+# Valid: single replica with SQLite (should pass)
+helm lint --strict miroir -f miroir/tests/valid-single-replica-sqlite.yaml
+
+# Invalid: multiple replicas with SQLite (should fail with constraint error)
+helm lint --strict miroir -f miroir/tests/invalid-multi-replica-sqlite.yaml
+
+# Valid: multiple replicas with Redis (should pass)
+helm lint --strict miroir -f miroir/tests/valid-multi-replica-redis.yaml
+```
+
+## Test Cases
+
+| Test Case | Description | Expected Result |
+|-----------|-------------|-----------------|
+| `valid-single-replica-sqlite.yaml` | `replicas: 1, backend: sqlite` | ✅ Pass |
+| `invalid-multi-replica-sqlite.yaml` | `replicas: 2, backend: sqlite` | ❌ Fail with constraint error |
+| `valid-multi-replica-redis.yaml` | `replicas: 2, backend: redis` | ✅ Pass |

charts/miroir/tests/invalid-multi-replica-sqlite.yaml

@@ -0,0 +1,9 @@
+# Test case: replicas: 2, backend: sqlite
+# Expected: helm lint --strict fails (multiple replicas require Redis)
+---
+miroir:
+  replicas: 2
+
+taskStore:
+  backend: sqlite
+  path: /data/miroir-tasks.db

charts/miroir/tests/valid-multi-replica-redis.yaml

@@ -0,0 +1,9 @@
+# Test case: replicas: 2, backend: redis
+# Expected: helm lint --strict passes (multiple replicas with Redis)
+---
+miroir:
+  replicas: 2
+
+taskStore:
+  backend: redis
+  url: redis://redis:6379

charts/miroir/tests/valid-single-replica-sqlite.yaml

@@ -0,0 +1,9 @@
+# Test case: replicas: 1, backend: sqlite
+# Expected: helm lint --strict passes (single replica can use SQLite)
+---
+miroir:
+  replicas: 1
+
+taskStore:
+  backend: sqlite
+  path: /data/miroir-tasks.db

charts/miroir/values.schema.json

@@ -0,0 +1,76 @@
+{
+  "$schema": "http://json-schema.org/draft-7/schema#",
+  "title": "Miroir Helm Chart Values",
+  "type": "object",
+  "properties": {
+    "miroir": {
+      "type": "object",
+      "properties": {
+        "image": {
+          "type": "object",
+          "properties": {
+            "repository": { "type": "string" },
+            "tag": { "type": "string" }
+          }
+        },
+        "replicas": {
+          "type": "integer",
+          "minimum": 1
+        },
+        "shards": {
+          "type": "integer",
+          "minimum": 1
+        },
+        "replicationFactor": {
+          "type": "integer",
+          "minimum": 1
+        },
+        "replicaGroups": {
+          "type": "integer",
+          "minimum": 1
+        },
+        "existingSecret": { "type": "string" }
+      }
+    },
+    "taskStore": {
+      "type": "object",
+      "properties": {
+        "backend": {
+          "type": "string",
+          "enum": ["sqlite", "redis"]
+        },
+        "path": { "type": "string" },
+        "url": { "type": "string" }
+      },
+      "required": ["backend"]
+    }
+  },
+  "if": {
+    "properties": {
+      "miroir": {
+        "properties": {
+          "replicas": {
+            "type": "integer",
+            "exclusiveMinimum": 1
+          }
+        },
+        "required": ["replicas"]
+      }
+    },
+    "required": ["miroir"]
+  },
+  "then": {
+    "properties": {
+      "taskStore": {
+        "properties": {
+          "backend": {
+            "const": "redis",
+            "errorMessage": "SQLite task store cannot run with multiple replicas; set taskStore.backend=redis"
+          }
+        },
+        "required": ["backend"]
+      }
+    },
+    "required": ["taskStore"]
+  }
+}

charts/miroir/values.yaml

@@ -0,0 +1,16 @@
+# Miroir Helm Chart Values
+
+miroir:
+  image:
+    repository: ghcr.io/jedarden/miroir
+    tag: ""  # defaults to Chart.appVersion
+  replicas: 1  # dev default: override to 2+ in production (requires taskStore.backend=redis)
+  shards: 64
+  replicationFactor: 1  # dev default: override to 2 in production
+  replicaGroups: 1  # dev default: override to 2 in production
+  existingSecret: ""  # name of K8s Secret with masterKey, nodeMasterKey, adminApiKey
+
+taskStore:
+  backend: sqlite  # sqlite | redis
+  path: /data/miroir-tasks.db
+  url: ""  # for redis: redis://host:6379