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/dead-code-scan.schema.json

@@ -0,0 +1,42 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "title": "Dead Code Scan",
+  "description": "Scan results for dead or redundant code",
+  "type": "object",
+  "required": ["target", "findings", "summary", "timestamp"],
+  "properties": {
+    "target": { "type": "string", "minLength": 1 },
+    "findings": {
+      "type": "array",
+      "items": {
+        "type": "object",
+        "required": ["id", "type", "location", "description", "confidence", "safe_to_remove"],
+        "properties": {
+          "id": { "type": "string", "pattern": "^DC-[0-9]{3}$" },
+          "type": {
+            "type": "string",
+            "enum": ["unused_export", "unreachable", "orphaned_file", "redundant", "stale_test", "unused_import", "commented_code"]
+          },
+          "location": { "type": "string", "minLength": 1 },
+          "symbol": { "type": "string" },
+          "description": { "type": "string", "minLength": 5 },
+          "evidence": { "type": "string" },
+          "confidence": { "type": "string", "enum": ["high", "medium", "low"] },
+          "safe_to_remove": { "type": "boolean" },
+          "removal_note": { "type": "string" }
+        }
+      }
+    },
+    "summary": {
+      "type": "object",
+      "required": ["total_findings"],
+      "properties": {
+        "total_findings": { "type": "integer", "minimum": 0 },
+        "by_type": { "type": "object" },
+        "high_confidence_count": { "type": "integer", "minimum": 0 },
+        "estimated_lines_removable": { "type": "integer", "minimum": 0 }
+      }
+    },
+    "timestamp": { "type": "string", "format": "date-time" }
+  }
+}