feat(tasks): add recurrence columns and model fields for native tasks

recurrence_series_id != "" is the real recurring indicator (IsRecurring
predates this feature and is never set). Adds parseWeekdays/formatWeekdays
for the comma-separated weekday-list column, and threads the five new
columns through scanNativeTasks and all four existing SELECT queries.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VTUSAEKfsPc6WGDq45yPHD

2 files changed, 125 insertions, 6 deletions

diff --git a/internal/store/native_tasks.go b/internal/store/native_tasks.go
index 7789a0d..c0a7a61 100644
--- a/internal/store/native_tasks.go
+++ b/internal/store/native_tasks.go
@@ -4,6 +4,8 @@ import (
 	"database/sql"
 	"encoding/json"
 	"errors"
+	"strconv"
+	"strings"
 	"time"
 
 	"task-dashboard/internal/models"
@@ -19,7 +21,8 @@ var ErrNativeTaskNotFound = errors.New("native task not found")
 // GetNativeTasks returns all non-completed native tasks.
 func (s *Store) GetNativeTasks() ([]models.Task, error) {
 	rows, err := s.db.Query(`
-		SELECT id, content, description, project_name, due_date, priority, completed, labels, created_at
+		SELECT id, content, description, project_name, due_date, priority, completed, labels, created_at,
+		       recurrence_freq, recurrence_interval, recurrence_weekdays, recurrence_series_id, next_occurrence_override
 		FROM native_tasks
 		WHERE completed = 0
 		ORDER BY CASE WHEN due_date IS NULL THEN 1 ELSE 0 END, due_date ASC, priority DESC
@@ -37,7 +40,8 @@ func (s *Store) GetNativeTasks() ([]models.Task, error) {
 // without double-counting against that separate fetch.
 func (s *Store) GetNativeTasksByDateRange(start, end time.Time) ([]models.Task, error) {
 	rows, err := s.db.Query(`
-		SELECT id, content, description, project_name, due_date, priority, completed, labels, created_at
+		SELECT id, content, description, project_name, due_date, priority, completed, labels, created_at,
+		       recurrence_freq, recurrence_interval, recurrence_weekdays, recurrence_series_id, next_occurrence_override
 		FROM native_tasks
 		WHERE completed = 0 AND due_date IS NOT NULL AND due_date >= ? AND due_date < ?
 		ORDER BY due_date ASC, priority DESC
@@ -57,7 +61,8 @@ func (s *Store) GetNativeTasksByDateRange(start, end time.Time) ([]models.Task,
 // ComputeDaySection to be marked IsOverdue.
 func (s *Store) GetOverdueNativeTasks(before time.Time) ([]models.Task, error) {
 	rows, err := s.db.Query(`
-		SELECT id, content, description, project_name, due_date, priority, completed, labels, created_at
+		SELECT id, content, description, project_name, due_date, priority, completed, labels, created_at,
+		       recurrence_freq, recurrence_interval, recurrence_weekdays, recurrence_series_id, next_occurrence_override
 		FROM native_tasks
 		WHERE completed = 0 AND due_date IS NOT NULL AND due_date < ?
 		ORDER BY due_date ASC, priority DESC
@@ -72,7 +77,8 @@ func (s *Store) GetOverdueNativeTasks(before time.Time) ([]models.Task, error) {
 // GetUndatedNativeTasks returns non-completed native tasks with no due date.
 func (s *Store) GetUndatedNativeTasks() ([]models.Task, error) {
 	rows, err := s.db.Query(`
-		SELECT id, content, description, project_name, due_date, priority, completed, labels, created_at
+		SELECT id, content, description, project_name, due_date, priority, completed, labels, created_at,
+		       recurrence_freq, recurrence_interval, recurrence_weekdays, recurrence_series_id, next_occurrence_override
 		FROM native_tasks
 		WHERE completed = 0 AND due_date IS NULL
 		ORDER BY priority DESC, created_at ASC
@@ -173,7 +179,12 @@ func scanNativeTasks(rows interface {
 		var t models.Task
 		var labelsJSON string
 		var dueDateStr *string
-		if err := rows.Scan(&t.ID, &t.Content, &t.Description, &t.ProjectName, &dueDateStr, &t.Priority, &t.Completed, &labelsJSON, &t.CreatedAt); err != nil {
+		var weekdaysStr string
+		var nextOverrideStr string
+		if err := rows.Scan(
+			&t.ID, &t.Content, &t.Description, &t.ProjectName, &dueDateStr, &t.Priority, &t.Completed, &labelsJSON, &t.CreatedAt,
+			&t.RecurrenceFreq, &t.RecurrenceInterval, &weekdaysStr, &t.RecurrenceSeriesID, &nextOverrideStr,
+		); err != nil {
 			return nil, err
 		}
 		if dueDateStr != nil {
@@ -188,7 +199,41 @@ func scanNativeTasks(rows interface {
 		if err := json.Unmarshal([]byte(labelsJSON), &t.Labels); err != nil {
 			t.Labels = nil
 		}
+		t.RecurrenceWeekdays = parseWeekdays(weekdaysStr)
+		if nextOverrideStr != "" {
+			if parsed, err := time.Parse("2006-01-02", nextOverrideStr); err == nil {
+				t.NextOccurrenceOverride = &parsed
+			}
+		}
 		tasks = append(tasks, t)
 	}
 	return tasks, rows.Err()
 }
+
+// parseWeekdays parses a comma-separated list of 0-6 ints (e.g. "1,3,5"),
+// returning nil for an empty string.
+func parseWeekdays(s string) []int {
+	if s == "" {
+		return nil
+	}
+	parts := strings.Split(s, ",")
+	weekdays := make([]int, 0, len(parts))
+	for _, p := range parts {
+		if n, err := strconv.Atoi(strings.TrimSpace(p)); err == nil {
+			weekdays = append(weekdays, n)
+		}
+	}
+	return weekdays
+}
+
+// formatWeekdays is the inverse of parseWeekdays.
+func formatWeekdays(weekdays []int) string {
+	if len(weekdays) == 0 {
+		return ""
+	}
+	strs := make([]string, len(weekdays))
+	for i, d := range weekdays {
+		strs[i] = strconv.Itoa(d)
+	}
+	return strings.Join(strs, ",")
+}
diff --git a/internal/store/native_tasks_test.go b/internal/store/native_tasks_test.go
index 5c11d3a..0a87bfa 100644
--- a/internal/store/native_tasks_test.go
+++ b/internal/store/native_tasks_test.go
@@ -7,6 +7,8 @@ import (
 	"testing"
 	"time"
 
+	"task-dashboard/internal/models"
+
 	_ "github.com/mattn/go-sqlite3"
 )
 
@@ -33,7 +35,12 @@ func newNativeTasksTestStore(t *testing.T) *Store {
 			completed BOOLEAN DEFAULT 0,
 			labels TEXT DEFAULT '[]',
 			created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
-			updated_at DATETIME DEFAULT CURRENT_TIMESTAMP
+			updated_at DATETIME DEFAULT CURRENT_TIMESTAMP,
+			recurrence_freq TEXT DEFAULT '',
+			recurrence_interval INTEGER DEFAULT 1,
+			recurrence_weekdays TEXT DEFAULT '',
+			recurrence_series_id TEXT DEFAULT '',
+			next_occurrence_override TEXT DEFAULT ''
 		)
 	`); err != nil {
 		t.Fatal(err)
@@ -94,3 +101,70 @@ func TestRescheduleNativeTask_UnknownID_ReturnsErrNotFound(t *testing.T) {
 		t.Fatalf("expected ErrNativeTaskNotFound, got %v", err)
 	}
 }
+
+func TestGetNativeTasks_ParsesRecurrenceFields(t *testing.T) {
+	s := newNativeTasksTestStore(t)
+	if _, err := s.db.Exec(`
+		INSERT INTO native_tasks (id, content, due_date, recurrence_freq, recurrence_interval, recurrence_weekdays, recurrence_series_id, next_occurrence_override)
+		VALUES ('rec-1', 'Recurring task', '2026-07-13', 'weekly', 2, '1,3,5', 'series-abc', '2026-07-27')
+	`); err != nil {
+		t.Fatal(err)
+	}
+
+	tasks, err := s.GetNativeTasks()
+	if err != nil {
+		t.Fatalf("GetNativeTasks: %v", err)
+	}
+
+	var found *models.Task
+	for i := range tasks {
+		if tasks[i].ID == "rec-1" {
+			found = &tasks[i]
+		}
+	}
+	if found == nil {
+		t.Fatal("expected to find rec-1")
+	}
+	if found.RecurrenceFreq != "weekly" {
+		t.Errorf("RecurrenceFreq = %q, want %q", found.RecurrenceFreq, "weekly")
+	}
+	if found.RecurrenceInterval != 2 {
+		t.Errorf("RecurrenceInterval = %d, want 2", found.RecurrenceInterval)
+	}
+	if len(found.RecurrenceWeekdays) != 3 || found.RecurrenceWeekdays[0] != 1 || found.RecurrenceWeekdays[1] != 3 || found.RecurrenceWeekdays[2] != 5 {
+		t.Errorf("RecurrenceWeekdays = %v, want [1 3 5]", found.RecurrenceWeekdays)
+	}
+	if found.RecurrenceSeriesID != "series-abc" {
+		t.Errorf("RecurrenceSeriesID = %q, want %q", found.RecurrenceSeriesID, "series-abc")
+	}
+	if found.NextOccurrenceOverride == nil || found.NextOccurrenceOverride.Format("2006-01-02") != "2026-07-27" {
+		t.Errorf("NextOccurrenceOverride = %v, want 2026-07-27", found.NextOccurrenceOverride)
+	}
+}
+
+func TestGetNativeTasks_NonRecurringTask_HasEmptyRecurrenceFields(t *testing.T) {
+	s := newNativeTasksTestStore(t)
+	// "real-1" (inserted by newNativeTasksTestStore) has no recurrence columns set.
+	tasks, err := s.GetNativeTasks()
+	if err != nil {
+		t.Fatalf("GetNativeTasks: %v", err)
+	}
+	var found *models.Task
+	for i := range tasks {
+		if tasks[i].ID == "real-1" {
+			found = &tasks[i]
+		}
+	}
+	if found == nil {
+		t.Fatal("expected to find real-1")
+	}
+	if found.RecurrenceSeriesID != "" {
+		t.Errorf("expected empty RecurrenceSeriesID for non-recurring task, got %q", found.RecurrenceSeriesID)
+	}
+	if found.RecurrenceWeekdays != nil {
+		t.Errorf("expected nil RecurrenceWeekdays for non-recurring task, got %v", found.RecurrenceWeekdays)
+	}
+	if found.NextOccurrenceOverride != nil {
+		t.Errorf("expected nil NextOccurrenceOverride for non-recurring task, got %v", found.NextOccurrenceOverride)
+	}
+}