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.
Classifies unconnected nets into optimal wiring methods (direct wire,
local/global label, power symbol, no-connect) based on pin distance,
crossing count, fanout, and net name patterns. Delegates all file
manipulation to apply_batch, inheriting collision detection and label
serialization for free.
Strategy concepts informed by KICAD-autowire (MIT, arashmparsa).
