Auto-save draft content on /create page to prevent accidental data loss

[realproject7]

Summary

Writers can lose their entire story if they accidentally navigate away, close the tab, or refresh the /create page. For a writing platform, this is critical to prevent.

Implementation

Auto-save to localStorage:

• Save title, content, genre, language, and hasDeadline to localStorage on every keystroke (debounced ~1 second)
• Key: plotlink_draft_create (or per-user key if wallet connected)
• On page load, restore from localStorage if a draft exists
• Show a small "Draft restored" indicator when content is recovered

Unsaved changes warning:

• Add beforeunload event listener when content is non-empty
• Browser shows native "Leave site? Changes you made may not be saved" dialog
• Remove listener after successful publish

Clear draft after publish:

• Delete localStorage draft after storyline is successfully created
• Also clear when user explicitly clicks a "Discard draft" button

Same pattern for Chain Plot page:

• Auto-save draft plot content when writing a new chapter
• Key: plotlink_draft_plot_{storylineId}
• Clear after successful plot submission

Acceptance Criteria

• Content auto-saved to localStorage on /create page (debounced)
• Draft restored on page revisit with indicator
• Browser warns before navigating away with unsaved content
• Draft cleared after successful publish
• "Discard draft" option available
• Same auto-save pattern on chain plot page
• Works across page refreshes and browser restarts