feat: builder 简历生成 + 轻度优化 + 简历导入交付副本

自内部仓库剥离深度优化与 RAG 知识库后的交付版本：
- Builder 对话式简历生成（FSM + 意图路由 LLM 兜底增强）
- 条目级轻度优化：事实覆盖门禁 + STAR/bullet 修复链，功能/简介/成果与技术栈同级保护
- 简历导入：DOCX/PDF 解析、结构归一、手机号脱敏
- PostgreSQL 运行时 + Alembic 迁移链

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

backend/tests/test_target_position_api.py

@@ -0,0 +1,55 @@
+"""Tests for the unified target-position write path."""
+
+from app.optimization_models import TargetPositionRequest
+
+
+def test_target_position_request_validation():
+    request = TargetPositionRequest(target_position=" 数据分析师 ")
+
+    assert request.target_position == " 数据分析师 "
+
+
+def test_set_target_position_updates_profile():
+    from app.optimization_flow import OptimizationFlowMixin
+
+    class FakeDatabase:
+        def __init__(self):
+            self.session = {
+                "id": "s1",
+                "stage": "RESUME_ENRICHING",
+                "revision": 3,
+                "profile": {"job_type": "校招"},
+                "draft_id": None,
+                "resume_id": "r1",
+            }
+
+        def transaction(self, immediate=False):
+            class Context:
+                def __enter__(self_inner):
+                    return object()
+
+                def __exit__(self_inner, *args):
+                    return False
+
+            return Context()
+
+        def update_session(self, connection, session_id, *, stage, profile, **kwargs):
+            self.session["profile"] = profile
+            return self.session
+
+    class Service(OptimizationFlowMixin):
+        pass
+
+    service = Service()
+    service.database = FakeDatabase()
+    service._session_or_404 = lambda connection, session_id: service.database.session
+
+    result = service.set_target_position("s1", " 数据分析师 ")
+
+    assert result == {
+        "target_position": "数据分析师",
+        "target_position_confirmed": True,
+    }
+    assert service.database.session["profile"]["target_position"] == "数据分析师"
+    assert service.database.session["profile"]["target_position_confirmed"] is True
+    assert service.database.session["profile"]["job_type"] == "校招"