Docs: sync 6 files with recent code changes

[mintlify]

Updates documentation across 6 files to reflect recent code changes merged to main.

Changes:

• guides/app-features/csv-imports.mdx — Added "Supported date formats" section documenting the new DD/MM/YY CSV-only format with a note on 2-digit year interpretation.
• guides/app-features/statement-vault.mdx — Added "Reconciliation against existing transactions" section covering provider-backed account imports, matching logic, reconciliation state, import summary counts, and revert behavior.
• llm-support.mdx — Updated ASSISTANT_MAX_TOOL_CALL_ITERATIONS default from 5 to 8, corrected worst-case timeout math, and added a note about the no-tools grace turn.
• development/mcp.mdx — Expanded tool tables to reflect the full current registry: added get_merchants, get_recurring_transactions, get_valuations, record_valuation, a new Preview tools section with get_insights, and updated descriptions for get_transactions, get_accounts, get_balance_sheet, and get_income_statement.
• features/recurring-transactions.mdx — Added a note to "Mark as recurring" explaining the button is disabled upfront when a matching manual recurring transaction already exists.
• providers/enable-banking.mdx — Added "Known bank-specific behavior" section documenting N26's PERIOD_INVALID error shape and Sure's automatic shorter-window retry.

[mintlify]

Preview deployment for your docs. Learn more about Mintlify Previews.

Project	Status	Preview	Updated (UTC)
sure	🟢 Ready	View Preview	Aug 22, 2026, 2:19 AM

💡 Tip: Enable Workflows to automatically generate PRs for you.