Implement linear task chains and recurring maintenance buckets

Backend, web timeline, and Android widget wiring for the last two
unimplemented items from doot-future-task-scheduling-ideas.

Chains: task_chains table + chain_id/chain_position/chain_unlocked on
native_tasks (migration 026), WIP-limit-1 advancement hooked into
CompleteNativeTask, locked tasks excluded from all date-based queries,
5 new /api/widget/chains* endpoints, an N/M position badge on web and
Android widget rows.

Buckets: maintenance_buckets table + bucket_id/bucket_state/
bucket_last_active_at on native_tasks (migration 027),
staleness-then-priority selection scoring, a new RunBucketCycleCheck
scheduler loop, 5 new endpoints including the distinct Defer action, a
Defer button on web and Android widget rows.

Also corrected stale "not yet approved" status headers on the two
already-shipped specs this work depended on (labels/projects, budgets/
availability) -- their headers were never updated after implementation.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EZ7ikw2ukGJFTHE3bJS7zL

1 files changed, 44 insertions, 6 deletions

diff --git a/internal/store/native_tasks.go b/internal/store/native_tasks.go
index 5d03bde..6f8ba7a 100644
--- a/internal/store/native_tasks.go
+++ b/internal/store/native_tasks.go
@@ -10,6 +10,7 @@ import (
 	"strings"
 	"time"
 
+	"task-dashboard/internal/config"
 	"task-dashboard/internal/models"
 )
 
@@ -24,7 +25,9 @@ var ErrNativeTaskNotFound = errors.New("native task not found")
 func (s *Store) GetNativeTasks() ([]models.Task, error) {
 	rows, err := s.db.Query(`
 		SELECT id, content, description, project_name, project_id, due_date, priority, completed, labels, created_at,
-		       recurrence_freq, recurrence_interval, recurrence_weekdays, recurrence_series_id, next_occurrence_override, estimated_minutes
+		       recurrence_freq, recurrence_interval, recurrence_weekdays, recurrence_series_id, next_occurrence_override, estimated_minutes,
+		       chain_id, chain_position, chain_unlocked,
+		       bucket_id, bucket_state, bucket_last_active_at
 		FROM native_tasks
 		WHERE completed = 0
 		ORDER BY CASE WHEN due_date IS NULL THEN 1 ELSE 0 END, due_date ASC, priority DESC
@@ -43,9 +46,12 @@ func (s *Store) GetNativeTasks() ([]models.Task, error) {
 func (s *Store) GetNativeTasksByDateRange(start, end time.Time) ([]models.Task, error) {
 	rows, err := s.db.Query(`
 		SELECT id, content, description, project_name, project_id, due_date, priority, completed, labels, created_at,
-		       recurrence_freq, recurrence_interval, recurrence_weekdays, recurrence_series_id, next_occurrence_override, estimated_minutes
+		       recurrence_freq, recurrence_interval, recurrence_weekdays, recurrence_series_id, next_occurrence_override, estimated_minutes,
+		       chain_id, chain_position, chain_unlocked,
+		       bucket_id, bucket_state, bucket_last_active_at
 		FROM native_tasks
 		WHERE completed = 0 AND due_date IS NOT NULL AND due_date >= ? AND due_date < ?
+		  AND (chain_id = '' OR chain_unlocked = 1)
 		ORDER BY due_date ASC, priority DESC
 	`, start, end)
 	if err != nil {
@@ -64,9 +70,12 @@ func (s *Store) GetNativeTasksByDateRange(start, end time.Time) ([]models.Task,
 func (s *Store) GetOverdueNativeTasks(before time.Time) ([]models.Task, error) {
 	rows, err := s.db.Query(`
 		SELECT id, content, description, project_name, project_id, due_date, priority, completed, labels, created_at,
-		       recurrence_freq, recurrence_interval, recurrence_weekdays, recurrence_series_id, next_occurrence_override, estimated_minutes
+		       recurrence_freq, recurrence_interval, recurrence_weekdays, recurrence_series_id, next_occurrence_override, estimated_minutes,
+		       chain_id, chain_position, chain_unlocked,
+		       bucket_id, bucket_state, bucket_last_active_at
 		FROM native_tasks
 		WHERE completed = 0 AND due_date IS NOT NULL AND due_date < ?
+		  AND (chain_id = '' OR chain_unlocked = 1)
 		ORDER BY due_date ASC, priority DESC
 	`, before)
 	if err != nil {
@@ -80,9 +89,13 @@ func (s *Store) GetOverdueNativeTasks(before time.Time) ([]models.Task, error) {
 func (s *Store) GetUndatedNativeTasks() ([]models.Task, error) {
 	rows, err := s.db.Query(`
 		SELECT id, content, description, project_name, project_id, due_date, priority, completed, labels, created_at,
-		       recurrence_freq, recurrence_interval, recurrence_weekdays, recurrence_series_id, next_occurrence_override, estimated_minutes
+		       recurrence_freq, recurrence_interval, recurrence_weekdays, recurrence_series_id, next_occurrence_override, estimated_minutes,
+		       chain_id, chain_position, chain_unlocked,
+		       bucket_id, bucket_state, bucket_last_active_at
 		FROM native_tasks
 		WHERE completed = 0 AND due_date IS NULL
+		  AND (chain_id = '' OR chain_unlocked = 1)
+		  AND bucket_state != 'dormant'
 		ORDER BY priority DESC, created_at ASC
 	`)
 	if err != nil {
@@ -96,7 +109,9 @@ func (s *Store) GetUndatedNativeTasks() ([]models.Task, error) {
 func (s *Store) GetNativeTaskByID(id string) (*models.Task, error) {
 	rows, err := s.db.Query(`
 		SELECT id, content, description, project_name, project_id, due_date, priority, completed, labels, created_at,
-		       recurrence_freq, recurrence_interval, recurrence_weekdays, recurrence_series_id, next_occurrence_override, estimated_minutes
+		       recurrence_freq, recurrence_interval, recurrence_weekdays, recurrence_series_id, next_occurrence_override, estimated_minutes,
+		       chain_id, chain_position, chain_unlocked,
+		       bucket_id, bucket_state, bucket_last_active_at
 		FROM native_tasks
 		WHERE id = ?
 	`, id)
@@ -166,6 +181,21 @@ func (s *Store) CompleteNativeTask(id string) error {
 		return err
 	}
 
+	if task.ChainID != "" {
+		if err := s.advanceChain(task.ChainID, task.ChainPosition); err != nil {
+			return err
+		}
+	}
+
+	if task.BucketID != "" {
+		now := config.Now()
+		if _, err := s.db.Exec(`
+			UPDATE native_tasks SET bucket_state = 'dormant', due_date = NULL, bucket_last_active_at = ?, updated_at = ? WHERE id = ?
+		`, now, now, id); err != nil {
+			return err
+		}
+	}
+
 	if task.RecurrenceSeriesID == "" {
 		return nil
 	}
@@ -334,7 +364,9 @@ func (s *Store) SetNextOccurrenceOverride(id string, date time.Time) error {
 func (s *Store) GetSeriesNeedingNextIteration(now time.Time) ([]models.Task, error) {
 	rows, err := s.db.Query(`
 		SELECT id, content, description, project_name, project_id, due_date, priority, completed, labels, created_at,
-		       recurrence_freq, recurrence_interval, recurrence_weekdays, recurrence_series_id, next_occurrence_override, estimated_minutes
+		       recurrence_freq, recurrence_interval, recurrence_weekdays, recurrence_series_id, next_occurrence_override, estimated_minutes,
+		       chain_id, chain_position, chain_unlocked,
+		       bucket_id, bucket_state, bucket_last_active_at
 		FROM native_tasks t1
 		WHERE recurrence_series_id != ''
 		  AND due_date IS NOT NULL AND due_date <= ?
@@ -395,12 +427,18 @@ func scanNativeTasks(rows interface {
 		var dueDateStr *string
 		var weekdaysStr string
 		var nextOverrideStr string
+		var bucketLastActiveAt sql.NullTime
 		if err := rows.Scan(
 			&t.ID, &t.Content, &t.Description, &t.ProjectName, &t.ProjectID, &dueDateStr, &t.Priority, &t.Completed, &labelsJSON, &t.CreatedAt,
 			&t.RecurrenceFreq, &t.RecurrenceInterval, &weekdaysStr, &t.RecurrenceSeriesID, &nextOverrideStr, &t.EstimatedMinutes,
+			&t.ChainID, &t.ChainPosition, &t.ChainUnlocked,
+			&t.BucketID, &t.BucketState, &bucketLastActiveAt,
 		); err != nil {
 			return nil, err
 		}
+		if bucketLastActiveAt.Valid {
+			t.BucketLastActiveAt = &bucketLastActiveAt.Time
+		}
 		if dueDateStr != nil {
 			if parsed, err := time.Parse(time.RFC3339, *dueDateStr); err == nil {
 				t.DueDate = &parsed