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/opamp.lib

@@ -0,0 +1,34 @@
+EESchema-LIBRARY Version 2.3
+#encoding utf-8
+#
+# OPAMP_X2_P8
+#
+DEF OPAMP_X2_P8 U 0 40 Y N 2 F N
+F0 "U" 100 150 50 H V C CNN
+F1 "OPAMP_X2_P8" 50 -150 50 H V L CNN
+F2 "" 0 0 50 H I C CNN
+F3 "" 0 0 50 H I C CNN
+ALIAS RC4558DGK RC4558D RC4558PW RC4558PS RC4558P TL082D TL082JG TL082P TL082PS TL082PW LM1458M LM1458MX LM1458N
+$FPLIST
+ IPC_SOIC8P127_490X600X175L83X41N
+$ENDFPLIST
+DRAW
+P 2 0 1 0 -180 -100 -140 -100 N
+P 2 0 1 0 -180 100 -140 100 N
+P 2 0 1 0 -160 120 -160 80 N
+P 4 0 1 0 -200 200 200 0 -200 -200 -200 200 N
+P 2 1 1 0 -20 60 20 60 N
+P 2 1 1 0 0 80 0 40 N
+P 2 1 1 0 20 -60 -20 -60 N
+X OUT 1 400 0 200 L 50 50 1 1 O
+X - 2 -400 -100 200 R 50 50 1 1 I
+X + 3 -400 100 200 R 50 50 1 1 I
+X V- 4 0 -300 200 U 50 50 1 1 W
+X V+ 8 0 300 200 D 50 50 1 1 W
+X + 5 -400 100 200 R 50 50 2 1 I
+X - 6 -400 -100 200 R 50 50 2 1 I
+X OUT 7 400 0 200 L 50 50 2 1 O
+ENDDRAW
+ENDDEF
+#
+#End Library