feat: 新增日程面板、复盘页面与 Agent 读写接口

- 日程：单次/每日/每周/每月重复，JSON 存储，月历按优先级着色圆点 + 悬停提示
- 复盘页：可自定义折线图卡片(SVG) + 每日心得总览(按日期/任务展开)
- Agent 接口：GET /api/agent/overview 读日程+进度，POST /api/agent/schedules 建日程(PPM_API_TOKEN Bearer 鉴权)
- 导出/导入/统计纳入日程与图表；47 项测试全绿

app/models.py

@@ -121,3 +121,59 @@ class PurgeInput(BaseModel):
     model_config = ConfigDict(extra="forbid")
 
     confirmation: str
+
+
+class ScheduleRecurrence(str, Enum):
+    none = "none"
+    daily = "daily"
+    weekly = "weekly"
+    monthly = "monthly"
+
+
+class ScheduleInput(BaseModel):
+    model_config = ConfigDict(extra="forbid", str_strip_whitespace=True)
+
+    title: Annotated[str, Field(min_length=1, max_length=120)]
+    description: Annotated[str, Field(max_length=2000)] = ""
+    date: date
+    time: Annotated[str | None, Field(max_length=5)] = None
+    recurrence: ScheduleRecurrence = ScheduleRecurrence.none
+    priority: Annotated[int, Field(ge=1, le=5)] = 3
+    state: Literal["active", "archived"] = "active"
+
+    @field_validator("time")
+    @classmethod
+    def validate_time(cls, value: str | None) -> str | None:
+        if value is None or value == "":
+            return None
+        if len(value) != 5 or value[2] != ":" or not value[:2].isdigit() or not value[3:].isdigit():
+            raise ValueError("时间必须是 HH:MM 格式")
+        hour, minute = int(value[:2]), int(value[3:])
+        if hour > 23 or minute > 59:
+            raise ValueError("时间必须是合法的时分")
+        return value
+
+
+class ScheduleUpdate(ScheduleInput):
+    expectedVersion: Annotated[int, Field(ge=1)]
+
+
+class ScheduleCompleteInput(BaseModel):
+    model_config = ConfigDict(extra="forbid")
+
+    date: date
+    completed: bool = True
+    expectedVersion: Annotated[int, Field(ge=1)]
+
+
+class ChartInput(BaseModel):
+    model_config = ConfigDict(extra="forbid", str_strip_whitespace=True)
+
+    title: Annotated[str, Field(min_length=1, max_length=80)]
+    taskId: str | None = None
+    metricId: str | None = None
+    days: Annotated[int, Field(ge=7, le=365)] = 30
+
+
+class ChartUpdate(ChartInput):
+    expectedVersion: Annotated[int, Field(ge=1)]