parse_lib_symbol_pins() now falls back to searching external .kicad_sym
library files when a symbol isn't embedded in the schematic's lib_symbols
section. Splits lib_id ("LibName:SymName") to locate the library file,
then parses pins using the bare symbol name.
Search order: schematic dir, libs/, ../libs/, project root, project
root/libs/, kicad/libs/, and sym-lib-table entries with ${KIPRJMOD}
substitution. Handles nonexistent directories gracefully.
Fixes add_power_symbol for script-generated schematics that reference
project library symbols without embedding them (e.g. D1/SMF5.0CA in
ESP32-P4-WIFI6-DEV-KIT library).
Ryan Malloy
e88f75f567