Fix: ticktick tasks update fails with Cannot read properties of undefined (reading 'id')

[leo-ashton]

Closes #5

Root Cause

Three issues:

1. update command lacked --project option — unlike complete and delete which take <projectId> <taskId>, the update CLI handler only accepted <taskId> and never passed a project ID to the library function.

2. resolveTaskId called with null projectId — without a project ID, resolveTaskId fell back to iterating all user projects. If any project returned a response with null/undefined task entries, t.id would throw.

3. TickTick update API returns 204 No Content — the update() function assumed the API would return the updated task object, but the TickTick API returns 204 with empty body on success. This caused task.id to crash even when resolveTaskId worked correctly.

Changes

File	Change
lib/tasks.js:134	update() extracts projectId from options and passes it to resolveTaskId instead of null
lib/tasks.js:469,484	resolveTaskId adds null guards: (data && data.tasks || []).find((t) => t && t.id && t.id.startsWith(taskId))
lib/tasks.js:486	resolveTaskId guards against null projects array from API
lib/tasks.js:148-159	update() handles 204 No Content — returns minimal task info when API response is empty
bin/ticktick.js:202	CLI passes --project option through to tasks.update()
test/tasks.test.js	Fix tasks.due test calls — due(days, options, deps) signature was receiving mock deps as options, causing real API calls

Usage

# Without --project (works, searches all projects)
ticktick tasks update TASK_ID --title "New Title"

# With --project (faster, searches only that project)
ticktick tasks update TASK_ID --project PROJECT_ID --title "New Title"

The --project option is optional. When provided, resolveTaskId searches only that project (fast path). When omitted, it falls back to the full-project search with null guards.