Add Wave contract schemas for pipeline validation

JSON Schema definitions for all pipeline handover contracts
including issue analysis, research, enhancement, and sync flows.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.wave/contracts/feature-exploration.schema.json

@@ -0,0 +1,52 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "title": "Feature Exploration",
+  "description": "Codebase exploration for feature implementation",
+  "type": "object",
+  "required": ["feature", "scope", "related_files", "timestamp"],
+  "properties": {
+    "feature": { "type": "string", "minLength": 1 },
+    "scope": { "type": "string", "enum": ["small", "medium", "large"] },
+    "related_files": {
+      "type": "array",
+      "minItems": 1,
+      "items": {
+        "type": "object",
+        "required": ["path", "relevance", "reason"],
+        "properties": {
+          "path": { "type": "string", "minLength": 1 },
+          "relevance": { "type": "string", "enum": ["primary", "secondary"] },
+          "reason": { "type": "string", "minLength": 1 },
+          "key_symbols": { "type": "array", "items": { "type": "string" } }
+        }
+      }
+    },
+    "patterns_to_follow": {
+      "type": "array",
+      "items": {
+        "type": "object",
+        "required": ["name"],
+        "properties": {
+          "name": { "type": "string" },
+          "example_file": { "type": "string" },
+          "relevance": { "type": "string", "enum": ["must_follow", "should_follow"] }
+        }
+      }
+    },
+    "affected_modules": { "type": "array", "items": { "type": "string" } },
+    "test_files": { "type": "array", "items": { "type": "string" } },
+    "risks": {
+      "type": "array",
+      "items": {
+        "type": "object",
+        "required": ["description", "severity"],
+        "properties": {
+          "description": { "type": "string" },
+          "severity": { "type": "string", "enum": ["high", "medium", "low"] },
+          "mitigation": { "type": "string" }
+        }
+      }
+    },
+    "timestamp": { "type": "string", "format": "date-time" }
+  }
+}