Add in-progress state to tasks

Introduce IN_PROGRESS as a new task state between TODO and DONE across
the full stack: database enum, Go backend, GraphQL, MCP, and frontend.

The task state icon now cycles forward on click (TODO → IN_PROGRESS →
DONE → TODO), and the action dropdown provides explicit "Move to"
options for any state transition. The "All" tab supports drag-and-drop
between state sections to change a task's state.

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

pkg/coredata/migrations/20260402T120000Z.sql

@@ -0,0 +1,15 @@
+-- Copyright (c) 2025-2026 Probo Inc <hello@getprobo.com>.
+--
+-- Permission to use, copy, modify, and/or distribute this software for any
+-- purpose with or without fee is hereby granted, provided that the above
+-- copyright notice and this permission notice appear in all copies.
+--
+-- THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+-- REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+-- AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+-- INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+-- LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+-- OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+-- PERFORMANCE OF THIS SOFTWARE.
+
+ALTER TYPE task_state ADD VALUE 'IN_PROGRESS' BEFORE 'DONE';

pkg/coredata/task_state.go

@@ -20,17 +20,19 @@ import (
 )
 
 type (
-	TaskState uint8
+	TaskState string
 )
 
 const (
-	TaskStateTodo TaskState = iota
-	TaskStateDone
+	TaskStateTodo       TaskState = "TODO"
+	TaskStateInProgress TaskState = "IN_PROGRESS"
+	TaskStateDone       TaskState = "DONE"
 )
 
 func TaskStates() []TaskState {
 	return []TaskState{
 		TaskStateTodo,
+		TaskStateInProgress,
 		TaskStateDone,
 	}
 }
@@ -40,13 +42,11 @@ func (ts TaskState) MarshalText() ([]byte, error) {
 }
 
 func (ts *TaskState) UnmarshalText(data []byte) error {
-	val := string(data)
+	val := TaskState(data)
 
 	switch val {
-	case TaskStateTodo.String():
-		*ts = TaskStateTodo
-	case TaskStateDone.String():
-		*ts = TaskStateDone
+	case TaskStateTodo, TaskStateInProgress, TaskStateDone:
+		*ts = val
 	default:
 		return fmt.Errorf("invalid TaskState value: %q", val)
 	}
@@ -55,16 +55,7 @@ func (ts *TaskState) UnmarshalText(data []byte) error {
 }
 
 func (ts TaskState) String() string {
-	var val string
-
-	switch ts {
-	case TaskStateTodo:
-		val = "TODO"
-	case TaskStateDone:
-		val = "DONE"
-	}
-
-	return val
+	return string(ts)
 }
 
 func (ts *TaskState) Scan(value any) error {