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/app/resume_api_models.py

@@ -0,0 +1,68 @@
+"""Pydantic contracts for resume content, editing, and optimization APIs."""
+
+from __future__ import annotations
+
+from datetime import datetime
+from typing import Any, Literal
+
+from pydantic import BaseModel, ConfigDict, Field
+
+
+class BusinessResume(BaseModel):
+    id: str
+    session_id: str
+    revision: int
+    content: dict[str, Any]
+    created_at: datetime
+    updated_at: datetime
+
+
+class ResumePatchOperation(BaseModel):
+    model_config = ConfigDict(extra="forbid")
+
+    type: Literal[
+        "update_basics", "update_entry", "update_bullet", "delete_entry", "delete_bullet",
+        "update_skill_groups", "update_profile_summary"
+    ]
+    entry_id: str | None = None
+    bullet_id: str | None = None
+    fields: dict[str, Any] | None = None
+    text: str | None = None
+    skills: list[str] | None = Field(default=None, max_length=80)
+
+
+class ResumePatchRequest(BaseModel):
+    model_config = ConfigDict(extra="forbid")
+
+    expected_revision: int = Field(ge=1)
+    operation: ResumePatchOperation
+
+
+class OptimizeRequest(BaseModel):
+    model_config = ConfigDict(extra="forbid")
+
+    entry_id: str = Field(min_length=1, max_length=64)
+    instruction: str | None = Field(default=None, max_length=200)
+
+
+class OptimizeEntryRequest(BaseModel):
+    model_config = ConfigDict(extra="forbid")
+
+    entry_id: str = Field(min_length=1, max_length=64)
+
+class SkillRecommendationRequest(BaseModel):
+    model_config = ConfigDict(extra="forbid")
+
+    question: str = Field(min_length=2, max_length=240)
+
+
+class SkillRecommendationCandidate(BaseModel):
+    skill: str = Field(min_length=1, max_length=48)
+    category: str = Field(min_length=1, max_length=48)
+    reason: str = Field(min_length=1, max_length=160)
+    evidence_supported: bool = False
+
+
+class SkillRecommendationResponse(BaseModel):
+    candidates: list[SkillRecommendationCandidate] = Field(default_factory=list, max_length=12)
+