docs: restore detailed design documents

Restored the following documents that were removed in Black-white-box-Merge:
- docs/detailed-design/ (9 detailed design documents + append_doc.py)
- docs/development-paradigm.md (development paradigm flowchart)
- docs/test-report.md (test report)
- AGENTS.md (project instructions)
- _AI_USAGE_LOG.md (AI usage log)
- CLAUDE.md (project instructions)
- sample/ (4 example files)

sample/SIMPLE-output.json

@@ -0,0 +1,35 @@
+{
+  "program": "SIMPLE",
+  "version": "3.0",
+  "generated_at": "2026-08-22T22:00:00",
+  "test_data": [
+    {
+      "id": 1,
+      "description": "基本赋值测试",
+      "input": {
+        "BILL-RECORD": {
+          "BR-AMT": "000150000",
+          "BR-STATUS": "A",
+          "BR-DATE": "20260522"
+        }
+      },
+      "expected_output": {
+        "DISPLAY": [
+          "000150000",
+          "A",
+          "20260522"
+        ]
+      },
+      "working_storage": {
+        "BR-AMT": "000150000",
+        "BR-STATUS": "A",
+        "BR-DATE": "20260522"
+      }
+    }
+  ],
+  "coverage": {
+    "branch_coverage": "100%",
+    "total_branches": 0,
+    "covered_branches": 0
+  }
+}