Phase 2: Add reasoning and TipTap content endpoints

- Extend Document model with reasoning_type, confidence, reasoning_steps, model_source, tiptap_content fields
- Add new endpoints:
  - GET /documents/{id}/reasoning - Get reasoning metadata
  - PATCH /documents/{id}/reasoning - Update reasoning metadata
  - GET /documents/{id}/reasoning-panel - Get reasoning panel data for UI
  - POST /documents/{id}/reasoning-steps - Add reasoning step
  - DELETE /documents/{id}/reasoning-steps/{step} - Delete reasoning step
  - GET /documents/{id}/content?format=tiptap|markdown - Get content in TipTap or Markdown
  - PUT /documents/{id}/content - Update content (supports both TipTap JSON and Markdown)
- Add TipTap to Markdown conversion
- Update database schema with new columns
- Add comprehensive tests for all new endpoints
- All 37 tests passing

app/schemas/document.py

@@ -1,6 +1,15 @@
 from datetime import datetime
+from enum import Enum
+from typing import Any
 
-from pydantic import BaseModel, Field
+from pydantic import BaseModel, Field, field_validator
+
+
+class ReasoningType(str, Enum):
+    CHAIN = "chain"
+    IDEA = "idea"
+    CONTEXT = "context"
+    REFLECTION = "reflection"
 
 
 class DocumentCreate(BaseModel):
@@ -18,6 +27,19 @@ class DocumentContentUpdate(BaseModel):
     content: str = Field(..., max_length=1_000_000)  # 1MB limit
 
 
+# Phase 2: TipTap Content Update - Union to support both legacy string and new TipTap/Markdown formats
+class TipTapContentUpdate(BaseModel):
+    content: dict[str, Any] | str  # TipTap JSON object or Markdown string
+    format: str = "tiptap"
+
+    @field_validator("format")
+    @classmethod
+    def validate_format(cls, v: str) -> str:
+        if v not in ("tiptap", "markdown"):
+            raise ValueError("format must be 'tiptap' or 'markdown'")
+        return v
+
+
 class TagInfo(BaseModel):
     id: str
     name: str
@@ -26,6 +48,67 @@ class TagInfo(BaseModel):
     model_config = {"from_attributes": True}
 
 
+# Phase 2: Reasoning Step Schema
+class ReasoningStep(BaseModel):
+    step: int
+    thought: str = Field(..., max_length=2000)
+    conclusion: str | None = Field(None, max_length=2000)
+
+
+# Phase 2: Reasoning Metadata Schema
+class ReasoningMetadata(BaseModel):
+    reasoning_type: ReasoningType | None = None
+    confidence: float | None = None
+    reasoning_steps: list[ReasoningStep] = []
+    model_source: str | None = None
+
+    model_config = {"protected_namespaces": ()}
+
+    @field_validator("confidence")
+    @classmethod
+    def validate_confidence(cls, v: float | None) -> float | None:
+        if v is not None and (v < 0.0 or v > 1.0):
+            raise ValueError("confidence must be between 0.0 and 1.0")
+        return v
+
+
+# Phase 2: Reasoning Update Schema
+class ReasoningUpdate(BaseModel):
+    reasoning_type: ReasoningType | None = None
+    confidence: float | None = None
+    reasoning_steps: list[ReasoningStep] | None = None
+    model_source: str | None = None
+
+    model_config = {"protected_namespaces": ()}
+
+    @field_validator("confidence")
+    @classmethod
+    def validate_confidence(cls, v: float | None) -> float | None:
+        if v is not None and (v < 0.0 or v > 1.0):
+            raise ValueError("confidence must be between 0.0 and 1.0")
+        return v
+
+
+# Phase 2: Add Reasoning Step Schema
+class ReasoningStepAdd(BaseModel):
+    thought: str = Field(..., min_length=1, max_length=2000)
+    conclusion: str | None = Field(None, max_length=2000)
+
+
+# Phase 2: TipTap Content Response
+class TipTapContentResponse(BaseModel):
+    content: dict[str, Any] | str
+    format: str
+
+
+# Phase 2: Reasoning Panel Schema
+class ReasoningPanel(BaseModel):
+    document_id: str
+    has_reasoning: bool
+    reasoning: ReasoningMetadata | None = None
+    editable: bool = True
+
+
 class DocumentResponse(BaseModel):
     id: str
     title: str
@@ -36,8 +119,14 @@ class DocumentResponse(BaseModel):
     tags: list[TagInfo] = []
     created_at: datetime
     updated_at: datetime
+    # Phase 2: new fields
+    reasoning_type: ReasoningType | None = None
+    confidence: float | None = None
+    reasoning_steps: list[ReasoningStep] = []
+    model_source: str | None = None
+    tiptap_content: dict[str, Any] | None = None
 
-    model_config = {"from_attributes": True}
+    model_config = {"from_attributes": True, "protected_namespaces": ()}
 
 
 class DocumentBriefResponse(BaseModel):