add_label bypasses kicad-sch-api serializer entirely — generates
s-expression strings and inserts them directly into the .kicad_sch
file via atomic write. Fixes two upstream bugs: global labels silently
dropped on save (serializer never iterates "global_label" key), and
local labels raising TypeError (parameter signature mismatch in
LabelCollection.add()).
add_power_symbol now falls back to sexp pin parsing when the API
returns None for custom library symbols (e.g. SMF5.0CA). Extracts
shared resolve_pin_position() utility used by both add_power_symbol
and batch operations.
Batch labels also fixed — collected as sexp strings during the batch
loop and inserted after sch.save() so the serializer can't overwrite
them.
Reduce _rc() and transform_pin_to_schematic() rounding from 3 to 2
decimal places to match KiCad's 0.01mm coordinate quantum — prevents
union-find misses when wire endpoints and sexp-parsed pin positions
differ at the sub-quantum level.
Use schematic stem as subdirectory inside .mckicad/ so multi-sheet
analysis outputs (connectivity.json, etc.) don't collide.
Root cause: kicad-sch-api doesn't back-populate comp.pins or sch.nets
on loaded schematics. All data is accessible through alternative APIs.
Pin extraction: use comp.get_symbol_definition().pins for metadata and
sch.list_component_pins(ref) for schematic-transformed positions.
Connectivity: new wire-walking engine using union-find on coordinates.
Walks wires, pin positions, labels, and power symbols to reconstruct
the net graph. Replaces broken ConnectivityAnalyzer/sch.nets fallbacks.
Eliminates 'unhashable type: Net' crash.
Hierarchy: use sch.sheets.get_sheet_hierarchy() instead of the broken
sheets.data.get("sheet", []) raw dict approach.
Labels: supplement sch.get_statistics() with sch.labels.get_statistics()
and sch.hierarchical_labels for accurate counts.
99 tests passing, lint clean.
