feat(code): show Draft badge on New task when input is unsubmitted

[fercgomes]

Summary

• Adds a small Draft badge on the "New task" sidebar item when the user has typed into the new-task input but not submitted it
• Reuses the existing persisted draft state (useDraftStore keyed on "task-input") — no new state machinery; the badge automatically disappears on submit because clearDraft already runs in the submit flow

Test plan

• Open the app — "New task" shows no badge
• Click "New task", type something into the editor, then navigate away (e.g. click a task or the Inbox) — "New task" now shows a Draft badge
• Reopen "New task" — the draft text is still in the editor, badge stays visible
• Submit the task — badge disappears, draft cleared
• Clear the editor manually (delete all text) — badge disappears
• Restart the app with a draft present — badge re-appears after the draft store hydrates from electronStorage

[greptile-apps]

_{Reviews (1): Last reviewed commit: "feat(code): show Draft badge on New task..." | Re-trigger Greptile}