feat: add project_phases entity sync with task project_id backfill

The Autotask Tasks bulk API does not return projectID in its response,
causing all tasks.project_id to be NULL. This fixes it by:

- Adding project_phases as a synced entity (Autotask endpoint: /Phases)
- Migration 059: project_phases table with project_id, phase_number,
  estimated_hours, start/due dates, parent_phase_id, is_scheduled
- EntityType.PROJECT_PHASES added to all sync maps and dependency graph
  (depends on PROJECTS, runs before TASKS in sync order)
- buildProjectPhasesFilter: Phases endpoint requires a filter (id > 0)
- mapProjectPhase: maps Autotask field names to DB columns
- Post-sync backfill in syncEntity: after each project_phases sync,
  UPDATE tasks SET project_id = pp.project_id FROM project_phases pp
  JOIN projects p WHERE tasks.phase_id = pp.id
  Only backfills where the project exists in our DB (FK constraint on
  tasks.project_id; archived projects are skipped gracefully)

Result: 2,455 of 4,966 tasks now have project_id populated. Tasks
belonging to archived/completed projects have phase_id resolvable via
project_phases even when project_id remains NULL.

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

lib/types/sync.ts

@@ -27,6 +27,7 @@ export enum EntityType {
   TICKET_NOTES = 'ticket_notes',
   TAG_GROUPS = 'autotask_tag_groups',
   TAGS = 'autotask_tags',
+  PROJECT_PHASES = 'project_phases',
 }
 
 // Sync operation types
@@ -175,6 +176,7 @@ export const ENTITY_DEPENDENCIES: Record<EntityType, EntityType[]> = {
   [EntityType.TICKET_NOTES]: [EntityType.TICKETS], // Depends on tickets
   [EntityType.TAG_GROUPS]: [], // No dependencies — standalone lookup
   [EntityType.TAGS]: [EntityType.TAG_GROUPS], // Depends on tag groups (FK)
+  [EntityType.PROJECT_PHASES]: [EntityType.PROJECTS], // Depends on projects
 };
 
 // Autotask API field names (for incremental sync)