feat: add goal management module (long-term goals with phases, milestones, reviews)

Backend:
- Goal model: title, description, status (active/paused/completed/abandoned),
  progress (auto-computed from milestones), target_date, category, color, icon
- GoalStep model: unified phase/milestone with parent nesting
- GoalReview model: periodic reflection with rating
- goal_tasks M2M: link existing tasks to goals
- /api/goals CRUD + steps CRUD + reviews + task linking + status toggle
- Progress auto-calculated from milestone completion ratio

Frontend:
- GoalPage: card grid with progress bars, status filter
- GoalDetailPage: step tree (phases > milestones), reviews, linked tasks
- GoalDialog: create/edit form with color/icon picker
- Goal navigation in AppHeader
- useGoalStore: full Pinia store for all goal operations

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

api/app/schemas/goal.py

@@ -0,0 +1,119 @@
+from pydantic import BaseModel, Field, field_validator
+from datetime import datetime, date
+from typing import Optional, List
+
+from app.schemas.category import CategoryResponse
+from app.schemas.task import TaskResponse
+
+
+# ============ GoalStep Schemas ============
+
+class GoalStepBase(BaseModel):
+    title: str = Field(..., max_length=200)
+    step_type: str = Field(..., pattern="^(phase|milestone)$")
+    status: str = Field(default="pending", pattern="^(pending|in_progress|completed)$")
+    target_date: Optional[date] = None
+    parent_id: Optional[int] = None
+    sort_order: int = Field(default=0)
+
+
+class GoalStepCreate(GoalStepBase):
+    pass
+
+
+class GoalStepUpdate(BaseModel):
+    title: Optional[str] = Field(None, max_length=200)
+    step_type: Optional[str] = Field(None, pattern="^(phase|milestone)$")
+    status: Optional[str] = Field(None, pattern="^(pending|in_progress|completed)$")
+    target_date: Optional[date] = None
+    parent_id: Optional[int] = None
+    sort_order: Optional[int] = None
+
+    @property
+    def clearable_fields(self) -> set:
+        return {"target_date", "parent_id"}
+
+
+class GoalStepResponse(GoalStepBase):
+    id: int
+    goal_id: int
+    reached_at: Optional[datetime] = None
+    created_at: datetime
+    children: List["GoalStepResponse"] = []
+
+    class Config:
+        from_attributes = True
+
+
+# ============ GoalReview Schemas ============
+
+class GoalReviewCreate(BaseModel):
+    content: str = Field(..., min_length=1)
+    rating: Optional[int] = Field(None, ge=1, le=5)
+
+
+class GoalReviewResponse(BaseModel):
+    id: int
+    goal_id: int
+    content: str
+    rating: Optional[int] = None
+    created_at: datetime
+
+    class Config:
+        from_attributes = True
+
+
+# ============ Goal Schemas ============
+
+class GoalBase(BaseModel):
+    title: str = Field(..., max_length=200)
+    description: Optional[str] = None
+    status: str = Field(default="active", pattern="^(active|paused|completed|abandoned)$")
+    target_date: Optional[date] = None
+    category_id: Optional[int] = None
+    color: str = Field(default="#FFB7C5", max_length=20)
+    icon: str = Field(default="flag", max_length=50)
+    sort_order: int = Field(default=0)
+
+
+class GoalCreate(GoalBase):
+    pass
+
+
+class GoalUpdate(BaseModel):
+    title: Optional[str] = Field(None, max_length=200)
+    description: Optional[str] = None
+    status: Optional[str] = Field(None, pattern="^(active|paused|completed|abandoned)$")
+    target_date: Optional[date] = None
+    category_id: Optional[int] = None
+    color: Optional[str] = Field(None, max_length=20)
+    icon: Optional[str] = Field(None, max_length=50)
+    sort_order: Optional[int] = None
+
+    @property
+    def clearable_fields(self) -> set:
+        return {"description", "target_date", "category_id"}
+
+
+class GoalListResponse(GoalBase):
+    id: int
+    progress: int
+    completed_at: Optional[datetime] = None
+    created_at: datetime
+    updated_at: datetime
+    category: Optional[CategoryResponse] = None
+    total_steps: int = 0
+    completed_steps: int = 0
+
+    class Config:
+        from_attributes = True
+
+
+class GoalDetailResponse(GoalListResponse):
+    steps: List[GoalStepResponse] = []
+    reviews: List[GoalReviewResponse] = []
+    tasks: List[TaskResponse] = []
+
+
+class GoalStatusUpdate(BaseModel):
+    status: str = Field(..., pattern="^(active|paused|completed|abandoned)$")