Eliminate the external kicad-sch-api dependency by migrating all MCP
tools to the internal SchDocument class built on sexp_tree.py. This
fixes three serialization bugs (dropped global labels, TypeError on
local labels, mis-quoted property private keywords) and removes ~1,900
lines of workaround code.
New modules:
- sexp_tree.py: S-expression parser and round-trip serializer
- sch_document.py: schematic read/write/mutate API
- lib_resolver.py: symbol library search and resolution
- sch_helpers.py: shared load/validate/expand helpers
Migrated all 9 tool files, resources, and tests. Removed 5 workaround
functions from sexp_parser.py. 531 tests pass, ruff + mypy clean.
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.
