Initial commit: MIKILAB KiCad personal library

Self-contained KiCad library (symbols, footprints, 3D models, docs,
import/check tooling) with no dependency on kicad-personal-library.

- Fixed sym-lib-table/fp-lib-table: single (version 7) header, one entry
  per library, MIKILAB_<name> nicknames, ${KIPRJMOD}-relative URIs
- Resolved the SOT95P280X145-5N footprint collision (TPS7A2012PDBVR vs
  TPS7A2018PDBVR): confirmed byte-identical modulo KiCad's internal
  tedit timestamp, unified into one shared footprint
- Resolved a case-insensitive filename collision between the official
  Diode.kicad_sym and a custom diode.kicad_sym
- Wrapped standalone footprints (ESP32-S31-WROOM-3, IC_TPS63020DSJT,
  SOT95P280X145-5N) into their own .pretty libraries so they're
  actually registered in fp-lib-table
- Fixed broken symbol->footprint references (including one pointing at
  a nonexistent easyeda2kicad library)
- Added scripts/check_library.py, import_component.py, add_component.py,
  import_batch.py, and lib_common.py

legacy/symbols/switch.lib

@@ -0,0 +1,27 @@
+EESchema-LIBRARY Version 2.3
+#encoding utf-8
+#
+# SPST2
+#
+DEF SPST2 SW 0 40 Y Y 1 F N
+F0 "SW" 0 250 60 H V C CNN
+F1 "SPST2" 0 -250 60 H V C CNN
+F2 "" 0 0 60 H V C CNN
+F3 "" 0 0 60 H V C CNN
+$FPLIST
+ 219-2M*
+$ENDFPLIST
+DRAW
+S -300 200 300 -200 0 1 0 N
+S -100 -50 0 -150 0 1 0 F
+S -100 -50 100 -150 0 1 0 N
+S -100 150 0 50 0 1 0 F
+S -100 150 100 50 0 1 0 N
+X A1 1 -500 100 200 R 50 50 1 1 P
+X B1 2 500 100 200 L 50 50 1 1 P
+X A2 3 -500 -100 200 R 50 50 1 1 P
+X B2 4 500 -100 200 L 50 50 1 1 P
+ENDDRAW
+ENDDEF
+#
+#End Library