New modules:
- patterns/ library: decoupling bank, pull resistor, crystal oscillator
placement with power symbol attachment and grid math helpers
- tools/batch.py: atomic file-based batch operations with dry_run
- tools/power_symbols.py: add_power_symbol with auto #PWR refs
- tools/schematic_patterns.py: MCP wrappers for pattern library
- tools/schematic_edit.py: modify/remove components, title blocks, annotations
- resources/schematic.py: schematic data resources
43 new tests (99 total), lint clean.
