Use configured timezone throughout codebase

- Add config/timezone.go with timezone utilities:
  - SetDisplayTimezone(), GetDisplayTimezone()
  - Now(), Today() - current time/date in display TZ
  - ParseDateInDisplayTZ(), ToDisplayTZ() - parsing helpers

- Initialize timezone at startup in main.go

- Update all datetime logic to use configured timezone:
  - handlers/handlers.go - all time.Now() calls
  - handlers/timeline.go - date parsing
  - handlers/timeline_logic.go - now calculation
  - models/atom.go - ComputeUIFields()
  - models/timeline.go - ComputeDaySection()
  - api/plantoeat.go - meal date parsing
  - api/todoist.go - due date parsing
  - api/trello.go - due date parsing

This ensures all dates/times display correctly regardless
of server timezone setting.

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

1 files changed, 0 insertions, 46 deletions

diff --git a/issues/phase4_step2_efficient_sync.md b/issues/phase4_step2_efficient_sync.md
deleted file mode 100644
index 92fa03c..0000000
--- a/issues/phase4_step2_efficient_sync.md
+++ /dev/null
@@ -1,46 +0,0 @@
-# Phase 4 Step 2: Efficient Sync Research & Implementation
-
-## Status: COMPLETE
-
-## Goal
-Improve the efficiency of data synchronization to reduce API calls and latency. Previously, the dashboard fetched all data on every refresh.
-
-## Implementation
-
-### Todoist Sync API v9
-- **Endpoint**: `https://api.todoist.com/sync/v9/sync`
-- **Method**: POST with `sync_token` and `resource_types`
-- **Full sync**: When token is `*` or empty, returns all items
-- **Incremental sync**: With valid token, returns only changes since last sync
-- **Response**: Contains `sync_token` (for next request), `full_sync` flag, `items`, `projects`
-
-### Storage
-- New `sync_tokens` table in SQLite for persisting tokens across restarts
-- Store methods: `GetSyncToken()`, `SetSyncToken()`, `ClearSyncToken()`
-- Incremental update methods: `UpsertTask()`, `DeleteTasksByIDs()`
-
-### Handler Logic
-- `fetchTasks()` uses Sync API with stored token
-- If `FullSync=true`: Replace all cached tasks
-- If `FullSync=false`: Merge changes (upsert active, delete completed/deleted)
-- Falls back to cached data on API errors
-
-### Trello Optimization
-- Added `fields` parameter to API calls to reduce response payload:
-  - `GetBoards()`: `fields=id,name`
-  - `GetCards()`: `fields=id,name,idList,due,url,idBoard`
-  - `getLists()`: `fields=id,name`
-
-## Files Modified
-- `migrations/003_add_sync_tokens.sql` (new)
-- `internal/store/sqlite.go` - Added sync token and incremental update methods
-- `internal/api/todoist.go` - Added Sync API support
-- `internal/api/interfaces.go` - Added Sync method to interface
-- `internal/api/trello.go` - Added field filtering
-- `internal/handlers/handlers.go` - Updated fetchTasks to use Sync API
-- `internal/handlers/handlers_test.go` - Updated mock to implement Sync
-
-## Benefits
-- **Todoist**: Reduced data transfer on subsequent syncs (only changes returned)
-- **Trello**: Smaller API responses (only required fields)
-- **Persistence**: Sync token survives restarts, enabling incremental sync on startup