Add resume and history system for makima (#1)

This PR implements a comprehensive resume and history system that enables:

1. **History Viewing**
   - View complete conversation history for contracts across all phases
   - View conversation history for individual tasks
   - View task output/tool call history with timestamps
   - View checkpoint history
   - Timeline view showing all activities

2. **Resume System**
   - Resume interrupted supervisor conversations with full context
   - Resume interrupted task conversations
   - Resume from specific checkpoints
   - Continue tasks from previous task state (worktree inheritance)

3. **Rewind/Restore Features**
   - Rewind code to any checkpoint (git restore)
   - Rewind conversation to any point
   - Create new branches from historical points
   - Fork tasks from any point in history

- New migration: 20250117000000_history_tables.sql
  - conversation_snapshots table for storing conversation state
  - history_events table for unified timeline
  - Added forking fields to tasks table
  - Added conversation_snapshot_id to task_checkpoints

- ConversationSnapshot, HistoryEvent, ConversationMessage
- Request/response types for resume and rewind operations
- Query filter types for history endpoints

- CRUD functions for conversation_snapshots
- CRUD functions for history_events
- Task conversation retrieval from task_events

- GET /api/v1/contracts/{id}/history
- GET /api/v1/contracts/{id}/supervisor/conversation
- GET /api/v1/mesh/tasks/{id}/conversation
- GET /api/v1/timeline
- POST /api/v1/contracts/{id}/supervisor/resume
- POST /api/v1/mesh/tasks/{id}/rewind
- POST /api/v1/mesh/tasks/{id}/fork
- POST /api/v1/mesh/tasks/{id}/checkpoints/{cid}/resume
- POST /api/v1/mesh/tasks/{id}/checkpoints/{cid}/branch
- POST /api/v1/contracts/{id}/supervisor/conversation/rewind

- task-history: View task conversation history
- task-checkpoints: List task checkpoints
- resume: Resume supervisor after interruption
- task-resume-from: Resume task from checkpoint
- task-rewind: Rewind task code to checkpoint
- task-fork: Fork task from historical point
- rewind-conversation: Rewind supervisor conversation

1 files changed, 233 insertions, 0 deletions

diff --git a/makima/src/db/models.rs b/makima/src/db/models.rs
index 40d4109..4419580 100644
--- a/makima/src/db/models.rs
+++ b/makima/src/db/models.rs
@@ -1559,3 +1559,236 @@ pub struct RepositorySuggestionsQuery {
     /// Limit results (default: 10)
     pub limit: Option<i32>,
 }
+
+// =============================================================================
+// Resume and History System Types
+// =============================================================================
+
+/// Conversation snapshot for task resumption
+#[derive(Debug, Clone, FromRow, Serialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct ConversationSnapshot {
+    pub id: Uuid,
+    pub task_id: Uuid,
+    pub checkpoint_id: Option<Uuid>,
+    /// Snapshot type: 'auto', 'manual', 'checkpoint'
+    pub snapshot_type: String,
+    pub message_count: i32,
+    #[sqlx(json)]
+    pub conversation_state: serde_json::Value,
+    #[sqlx(json)]
+    pub metadata: Option<serde_json::Value>,
+    pub created_at: DateTime<Utc>,
+}
+
+/// History event for contract/task history tracking
+#[derive(Debug, Clone, FromRow, Serialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct HistoryEvent {
+    pub id: Uuid,
+    pub owner_id: Uuid,
+    pub contract_id: Option<Uuid>,
+    pub task_id: Option<Uuid>,
+    pub event_type: String,
+    pub event_subtype: Option<String>,
+    pub phase: Option<String>,
+    #[sqlx(json)]
+    pub event_data: serde_json::Value,
+    pub created_at: DateTime<Utc>,
+}
+
+/// Unified conversation message for API responses
+#[derive(Debug, Clone, Serialize, Deserialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct ConversationMessage {
+    pub id: String,
+    /// Message role: 'user', 'assistant', 'system', 'tool'
+    pub role: String,
+    pub content: String,
+    pub timestamp: DateTime<Utc>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub tool_calls: Option<Vec<ToolCallInfo>>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub tool_name: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub tool_input: Option<serde_json::Value>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub tool_result: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub is_error: Option<bool>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub token_count: Option<i32>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub cost_usd: Option<f64>,
+}
+
+/// Tool call information within a conversation message
+#[derive(Debug, Clone, Serialize, Deserialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct ToolCallInfo {
+    pub id: String,
+    pub name: String,
+    pub input: serde_json::Value,
+}
+
+/// Query filters for history endpoints
+#[derive(Debug, Deserialize, ToSchema, Default)]
+#[serde(rename_all = "camelCase")]
+pub struct HistoryQueryFilters {
+    pub phase: Option<String>,
+    pub event_types: Option<Vec<String>>,
+    pub from: Option<DateTime<Utc>>,
+    pub to: Option<DateTime<Utc>>,
+    pub limit: Option<i32>,
+    pub cursor: Option<String>,
+}
+
+/// Request to resume a supervisor
+#[derive(Debug, Deserialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct ResumeSupervisorRequest {
+    pub target_daemon_id: Option<Uuid>,
+    /// Resume mode: 'continue', 'restart_phase', 'from_checkpoint'
+    pub resume_mode: String,
+    pub checkpoint_id: Option<Uuid>,
+    pub additional_context: Option<String>,
+}
+
+/// Request to resume from a checkpoint
+#[derive(Debug, Deserialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct ResumeFromCheckpointRequest {
+    pub task_name: Option<String>,
+    pub plan: String,
+    pub include_conversation: Option<bool>,
+    pub target_daemon_id: Option<Uuid>,
+}
+
+/// Request to rewind a task to a checkpoint
+#[derive(Debug, Deserialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct RewindTaskRequest {
+    pub checkpoint_id: Option<Uuid>,
+    pub checkpoint_sha: Option<String>,
+    /// Preserve mode: 'discard', 'create_branch', 'stash'
+    pub preserve_mode: String,
+    pub branch_name: Option<String>,
+}
+
+/// Request to rewind a conversation
+#[derive(Debug, Deserialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct RewindConversationRequest {
+    pub to_message_id: Option<String>,
+    pub to_timestamp: Option<DateTime<Utc>>,
+    pub by_message_count: Option<i32>,
+    pub rewind_code: Option<bool>,
+}
+
+/// Request to fork a task
+#[derive(Debug, Deserialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct ForkTaskRequest {
+    /// Fork from type: 'checkpoint', 'timestamp', 'message_id'
+    pub fork_from_type: String,
+    pub fork_from_value: String,
+    pub new_task_name: String,
+    pub new_task_plan: String,
+    pub include_conversation: Option<bool>,
+    pub create_branch: Option<bool>,
+    pub branch_name: Option<String>,
+}
+
+/// Response for contract history endpoint
+#[derive(Debug, Serialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct ContractHistoryResponse {
+    pub contract_id: Uuid,
+    pub entries: Vec<HistoryEvent>,
+    pub total_count: i64,
+    pub cursor: Option<String>,
+}
+
+/// Response for task conversation endpoint
+#[derive(Debug, Serialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct TaskConversationResponse {
+    pub task_id: Uuid,
+    pub task_name: String,
+    pub status: String,
+    pub messages: Vec<ConversationMessage>,
+    pub total_tokens: Option<i32>,
+    pub total_cost: Option<f64>,
+}
+
+/// Response for supervisor conversation endpoint
+#[derive(Debug, Serialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct SupervisorConversationResponse {
+    pub contract_id: Uuid,
+    pub supervisor_task_id: Uuid,
+    pub phase: String,
+    pub last_activity: DateTime<Utc>,
+    pub pending_task_ids: Vec<Uuid>,
+    pub messages: Vec<ConversationMessage>,
+    pub spawned_tasks: Vec<TaskReference>,
+}
+
+/// Reference to a task for history/conversation responses
+#[derive(Debug, Serialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct TaskReference {
+    pub task_id: Uuid,
+    pub task_name: String,
+    pub status: String,
+    pub created_at: DateTime<Utc>,
+    pub completed_at: Option<DateTime<Utc>>,
+}
+
+/// Response for task rewind operation
+#[derive(Debug, Serialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct RewindTaskResponse {
+    pub task_id: Uuid,
+    pub rewinded_to: CheckpointInfo,
+    pub preserved_as: Option<PreservedState>,
+}
+
+/// Checkpoint information in rewind response
+#[derive(Debug, Serialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct CheckpointInfo {
+    pub checkpoint_number: i32,
+    pub sha: String,
+    pub message: String,
+}
+
+/// Preserved state information in rewind response
+#[derive(Debug, Serialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct PreservedState {
+    /// State type: 'branch' or 'stash'
+    pub state_type: String,
+    pub reference: String,
+}
+
+/// Response for task fork operation
+#[derive(Debug, Serialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct ForkTaskResponse {
+    pub new_task_id: Uuid,
+    pub source_task_id: Uuid,
+    pub fork_point: ForkPoint,
+    pub branch_name: Option<String>,
+    pub conversation_included: bool,
+    pub message_count: Option<i32>,
+}
+
+/// Fork point information in fork response
+#[derive(Debug, Serialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct ForkPoint {
+    pub fork_type: String,
+    pub checkpoint: Option<TaskCheckpoint>,
+    pub timestamp: DateTime<Utc>,
+}