feat: add government fee calculation to Plot Master and related doctypes

[github-actions]

Backport of #44 to version-15.

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• Added land_rent_rate field to Plot Type doctype (rates: Residential/Housing Estate/Religious Institution/Electricity/Water = 11, Commercial Residential = 21, Commercial/Lodge = 53)
• Added government fee fields to Plot Master (land_rent, premium, registration_prep_fee, govt_application_fee, govt_registration_fee, stamp_duty, total_govt_fees, total_plot_amount) — all calculated automatically on save, read-only, informational only (not posted to accounts)
• Added land_rent_rate display column to Land Acquisition Plot Type Rate child table (fetched from Plot Type)
• Added govt fee config fields to LandMS Settings (govt_appl_fee_amount, govt_registration_fee_amount, govt_premium_rate)
• Fixed two-column layout on Plot Master govt fees section and LandMS Settings govt fees section
• Fixed Sales Order TCB checkboxes side-by-side layout
• Fixed circular import in plot_master.py (lazy import of sync_land_acquisition_plot_summary)
• Replaced SR-based plot cost recalculation with LCV pattern
• Simplified plot handover serial status fix (reset only the one serial instead of cancelling all SRs for the LA)