Refactors _build_connectivity() into a two-layer state builder so the
union-find internals (pin_at, label_at, wire_segments) are accessible
to new analysis tools without duplicating the 200-line connectivity engine.
New tools:
- audit_wiring: trace all wires connected to a component, report per-pin
net membership with wire segment coordinates and connected pins
- remove_wires_by_criteria: bulk-remove wires by coordinate filters
(y, x, min/max ranges, tolerance) with dry_run preview support
- verify_connectivity: compare actual wiring against an expected
net-to-pin mapping, report matches/mismatches/missing nets
New sexp_parser utilities:
- parse_wire_segments: extract (wire ...) blocks with start/end/uuid
- remove_sexp_blocks_by_uuid: atomically remove blocks by UUID set
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.
