feat: remove workspace system, add pinned flows and label renames

Replace workspace system with pinned flows API (pin/unpin/list/reorder).
Rename user-facing labels: Tree→Flow, Procedure→Project. Add sidebar
nav sub-items for flow type filtering. Remove 11 workspace files,
add migrations 037-038, clean all workspace references.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/app/schemas/category.py

@@ -37,7 +37,6 @@ class CategoryResponse(CategoryBase):
     display_order: int
     is_active: bool
     color: Optional[str] = None
-    workspace_id: Optional[UUID] = None
     created_at: datetime
     updated_at: datetime
     tree_count: int = 0  # Computed field
@@ -55,7 +54,6 @@ class CategoryListResponse(BaseModel):
     display_order: int
     is_active: bool
     color: Optional[str] = None
-    workspace_id: Optional[UUID] = None
     tree_count: int = 0
 
     class Config:

backend/app/schemas/tree.py

@@ -245,3 +245,37 @@ class TreeValidationResponse(BaseModel):
     """Response for tree validation endpoint."""
     can_publish: bool
     errors: list[ValidationError] = []
+
+
+# --- Pinned Flows Schemas ---
+
+class PinnedFlowResponse(BaseModel):
+    """A pinned flow in the sidebar."""
+    id: UUID
+    tree_id: UUID
+    tree_name: str
+    tree_type: str
+    category_emoji: Optional[str] = None
+    category_name: Optional[str] = None
+    pinned_at: datetime
+    display_order: int
+
+    class Config:
+        from_attributes = True
+
+
+class PinnedFlowsListResponse(BaseModel):
+    """List of pinned flows."""
+    items: list[PinnedFlowResponse]
+    count: int
+
+
+class PinnedFlowReorderItem(BaseModel):
+    """Single item in a reorder request."""
+    tree_id: UUID
+    display_order: int
+
+
+class PinnedFlowReorderRequest(BaseModel):
+    """Request to reorder pinned flows."""
+    order: list[PinnedFlowReorderItem]

backend/app/schemas/workspace.py

@@ -1,39 +0,0 @@
-import uuid
-from datetime import datetime
-from typing import Optional
-from pydantic import BaseModel, Field
-
-
-class WorkspaceCreate(BaseModel):
-    name: str = Field(..., min_length=1, max_length=100)
-    slug: str = Field(..., min_length=1, max_length=100, pattern=r'^[a-z0-9-]+$')
-    description: Optional[str] = None
-    icon: Optional[str] = Field(None, max_length=10)
-    accent_color: Optional[str] = Field(None, pattern=r'^#[0-9a-fA-F]{6}$')
-    sort_order: int = 0
-
-
-class WorkspaceUpdate(BaseModel):
-    name: Optional[str] = Field(None, min_length=1, max_length=100)
-    slug: Optional[str] = Field(None, min_length=1, max_length=100, pattern=r'^[a-z0-9-]+$')
-    description: Optional[str] = None
-    icon: Optional[str] = Field(None, max_length=10)
-    accent_color: Optional[str] = Field(None, pattern=r'^#[0-9a-fA-F]{6}$')
-    sort_order: Optional[int] = None
-
-
-class WorkspaceResponse(BaseModel):
-    id: uuid.UUID
-    name: str
-    slug: str
-    description: Optional[str] = None
-    icon: Optional[str] = None
-    accent_color: Optional[str] = None
-    account_id: uuid.UUID
-    is_default: bool
-    sort_order: int
-    tree_count: int = 0
-    created_at: datetime
-    updated_at: datetime
-
-    model_config = {"from_attributes": True}