Add feature toggles system with settings UI (#74)

- Add feature_toggles table (migration 012)
- Add source_config table for future source selection (migration 013)
- Create settings page at /settings with:
  - Feature toggle management (enable/disable/create/delete)
  - Data source configuration (sync and toggle boards/calendars)
- Add store methods for feature toggles and source config
- Add GetCalendarList and GetTaskLists to Google API clients
- Document feature toggle workflow in DESIGN.md

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

1 files changed, 30 insertions, 0 deletions

diff --git a/internal/models/types.go b/internal/models/types.go
index e28d985..ab06ea2 100644
--- a/internal/models/types.go
+++ b/internal/models/types.go
@@ -114,6 +114,18 @@ type GoogleTask struct {
 	UpdatedAt time.Time  `json:"updated_at"`
 }
 
+// CalendarInfo represents basic info about a Google Calendar
+type CalendarInfo struct {
+	ID   string `json:"id"`
+	Name string `json:"name"`
+}
+
+// TaskListInfo represents basic info about a Google Tasks list
+type TaskListInfo struct {
+	ID   string `json:"id"`
+	Name string `json:"name"`
+}
+
 // Bug represents a bug report
 type Bug struct {
 	ID          int64      `json:"id"`
@@ -207,3 +219,21 @@ type CompletedTask struct {
 	DueDate     *time.Time `json:"due_date,omitempty"`
 	CompletedAt time.Time  `json:"completed_at"`
 }
+
+// SourceConfig represents a configurable item from a data source
+type SourceConfig struct {
+	ID        int64  `json:"id"`
+	Source    string `json:"source"`     // trello, todoist, gcal, gtasks
+	ItemType  string `json:"item_type"`  // board, project, calendar, tasklist
+	ItemID    string `json:"item_id"`
+	ItemName  string `json:"item_name"`
+	Enabled   bool   `json:"enabled"`
+}
+
+// FeatureToggle represents a feature flag
+type FeatureToggle struct {
+	ID          int64  `json:"id"`
+	Name        string `json:"name"`
+	Description string `json:"description"`
+	Enabled     bool   `json:"enabled"`
+}