Add task priority enum and rename priority to rank

The existing integer priority field represents positional ordering
within a state, not semantic importance. Rename it to rank and
introduce a new priority field with enum values URGENT, HIGH,
MEDIUM and LOW across the entire stack.

Rank is now scoped to (state, priority) so tasks are ordered
within each priority group. A generated priority_rank column
combines both fields into a single sortable integer for cursor
pagination.

Dragging a task across priority groups updates its priority
automatically based on the drop position neighbors. The backend
first moves the task to the new group then repositions it at the
target rank.

The migration defaults existing rows to MEDIUM priority and
backfills ranks per (state, priority) group.

Signed-off-by: Sacha Al Himdani <sacha@getprobo.com>

pkg/server/api/console/v1/schema.graphql

@@ -69,6 +69,26 @@ enum TaskState @goModel(model: "go.probo.inc/probo/pkg/coredata.TaskState") {
     DONE @goEnum(value: "go.probo.inc/probo/pkg/coredata.TaskStateDone")
 }
 
+enum TaskPriority
+    @goModel(model: "go.probo.inc/probo/pkg/coredata.TaskPriority") {
+    URGENT
+        @goEnum(
+            value: "go.probo.inc/probo/pkg/coredata.TaskPriorityUrgent"
+        )
+    HIGH
+        @goEnum(
+            value: "go.probo.inc/probo/pkg/coredata.TaskPriorityHigh"
+        )
+    MEDIUM
+        @goEnum(
+            value: "go.probo.inc/probo/pkg/coredata.TaskPriorityMedium"
+        )
+    LOW
+        @goEnum(
+            value: "go.probo.inc/probo/pkg/coredata.TaskPriorityLow"
+        )
+}
+
 enum EvidenceState
     @goModel(model: "go.probo.inc/probo/pkg/coredata.EvidenceState") {
     FULFILLED
@@ -507,7 +527,7 @@ enum MeasureOrderField
 
 enum TaskOrderField
     @goModel(model: "go.probo.inc/probo/pkg/coredata.TaskOrderField") {
-    PRIORITY
+    PRIORITY_RANK
     CREATED_AT
 }
 
@@ -2404,7 +2424,8 @@ type Task implements Node {
     name: String!
     description: String
     state: TaskState!
-    priority: Int!
+    priority: TaskPriority!
+    rank: Int!
     timeEstimate: Duration
     deadline: Datetime
     assignedTo: Profile @goField(forceResolver: true)
@@ -4274,6 +4295,7 @@ input CreateTaskInput {
     measureId: ID
     name: String!
     description: String
+    priority: TaskPriority!
     timeEstimate: Duration
     assignedToId: ID
     deadline: Datetime
@@ -4284,7 +4306,8 @@ input UpdateTaskInput {
     name: String
     description: String @goField(omittable: true)
     state: TaskState
-    priority: Int
+    priority: TaskPriority
+    rank: Int
     timeEstimate: Duration @goField(omittable: true)
     deadline: Datetime @goField(omittable: true)
     assignedToId: ID @goField(omittable: true)

pkg/server/api/console/v1/types/task.go

@@ -71,6 +71,7 @@ func NewTask(t *coredata.Task) *Task {
 		Description:  t.Description,
 		State:        t.State,
 		Priority:     t.Priority,
+		Rank:         t.Rank,
 		TimeEstimate: t.TimeEstimate,
 		Deadline:     t.Deadline,
 		CreatedAt:    t.CreatedAt,

pkg/server/api/console/v1/v1_resolver.go

@@ -4061,6 +4061,7 @@ func (r *mutationResolver) CreateTask(ctx context.Context, input types.CreateTas
 			OrganizationID: input.OrganizationID,
 			Name:           input.Name,
 			Description:    input.Description,
+			Priority:       input.Priority,
 			TimeEstimate:   input.TimeEstimate,
 			AssignedToID:   input.AssignedToID,
 			Deadline:       input.Deadline,
@@ -4099,6 +4100,7 @@ func (r *mutationResolver) UpdateTask(ctx context.Context, input types.UpdateTas
 			Description:  gqlutils.UnwrapOmittable(input.Description),
 			State:        input.State,
 			Priority:     input.Priority,
+			Rank:         input.Rank,
 			TimeEstimate: gqlutils.UnwrapOmittable(input.TimeEstimate),
 			Deadline:     gqlutils.UnwrapOmittable(input.Deadline),
 			AssignedToID: gqlutils.UnwrapOmittable(input.AssignedToID),