Add CSV and PDF export for local appraisals

[InfinityBowman]

Export local appraisals as CSV or PDF directly from the dashboard.

• CSV export includes all sub-items (AMSTAR2 checkboxes, ROB2/ROBINS-I signalling questions and domain judgments)
• PDF export renders the full checklist form (questions, answers, judgments, preliminary sections)
• Export individual appraisals or all at once via dropdown menu
• Reads answer data from Y.Doc for non-finalized checklists

[coderabbitai]

⚠️ Possible Duplicate Issue(s)

• Import/Export project data #266

🔗 Related PRs

#115 - 114 improve project overview page [merged]
#170 - 165 table output for data [merged]

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