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>

migrations/059_create_project_phases_table.sql

@@ -0,0 +1,30 @@
+-- Migration 059: Create project_phases table
+-- Project phases are groupings of tasks within an Autotask project.
+-- Tasks reference phases via phase_id. Syncing phases allows us to resolve
+-- tasks back to their parent project (tasks.phase_id → project_phases.id → project_phases.project_id).
+-- Autotask endpoint: /Phases
+
+CREATE TABLE IF NOT EXISTS project_phases (
+  id                      BIGINT PRIMARY KEY,
+  project_id              BIGINT, -- no FK: phases may reference completed/archived projects not in our DB
+  parent_phase_id         BIGINT,
+  title                   CHARACTER VARYING,
+  description             TEXT,
+  phase_number            CHARACTER VARYING,
+  estimated_hours         NUMERIC,
+  start_date_time         TIMESTAMP WITHOUT TIME ZONE,
+  due_date                TIMESTAMP WITHOUT TIME ZONE,
+  create_date_time        TIMESTAMP WITHOUT TIME ZONE,
+  last_activity_date_time TIMESTAMP WITHOUT TIME ZONE,
+  creator_resource_id     BIGINT,
+  is_scheduled            BOOLEAN DEFAULT FALSE,
+  external_id             CHARACTER VARYING,
+  synced_at               TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+  created_at              TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+  updated_at              TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+  is_deleted              BOOLEAN DEFAULT FALSE,
+  deleted_at              TIMESTAMP WITH TIME ZONE
+);
+
+CREATE INDEX IF NOT EXISTS idx_project_phases_project_id ON project_phases (project_id);
+CREATE INDEX IF NOT EXISTS idx_project_phases_is_deleted ON project_phases (is_deleted) WHERE is_deleted = FALSE;