test: align photoresistor-sensor fixtures + snapshots with 603b791 alias

Three failures introduced by 603b791 (which added
MAPPERS['photoresistor-sensor'] = MAPPERS['photoresistor'] so the
metadata-id 'photoresistor-sensor' resolves to a SPICE mapper):

- component-to-spice.test.ts "every mapped metadataId has a test fixture"
  flagged photoresistor-sensor as missing. Added a fixture entry that
  mirrors the photoresistor one — the part is electrically identical.

- examples-netlist-snapshot.test.ts > photoresistor-light and
  > nano-sensor-station snapshots now contain R_ldr_ldr + R_ldr_pull
  cards (correct LDR + 10k pull) instead of the previous
  R_autopull_n0 100M stub. This is the intended behaviour change:
  before the alias the LDR was unmapped and the netlist autopulled the
  net to ground with a 100M dummy; after the alias the SPICE deck
  carries the real divider topology. Regenerated only these two
  snapshot entries (vitest -u on the single file).

No production code changes.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

frontend/src/__tests__/__snapshots__/examples-netlist-snapshot.test.ts.snap

@@ -1392,7 +1392,8 @@ exports[`netlist snapshot — circuits (40 examples) > nano-sensor-station 1`] =
 V_VCC_RAIL vcc_rail 0 DC 5
 R_ntc_ntc vcc_rail n1 11441.484668193882
 R_ntc_pull n1 0 10000
-R_autopull_n0 n0 0 100Meg
+R_ldr_ldr vcc_rail n0 400000
+R_ldr_pull n0 0 10000
 .op
 .end"
 `;
@@ -1754,7 +1755,8 @@ R_autopull_n2 n2 0 100Meg
 exports[`netlist snapshot — circuits (40 examples) > photoresistor-light 1`] = `
 "* Velxio circuit
 V_VCC_RAIL vcc_rail 0 DC 5
-R_autopull_n0 n0 0 100Meg
+R_ldr_ldr vcc_rail n0 285714.28571428574
+R_ldr_pull n0 0 10000
 .op
 .end"
 `;

frontend/src/__tests__/component-to-spice.test.ts

@@ -97,6 +97,10 @@ const MINIMAL_FIXTURES: Record<string, Fixture> = {
   potentiometer: { pins: ['VCC', 'SIG', 'GND'], properties: { min: 0, max: 1023, value: 512 } },
   'ntc-temperature-sensor': { pins: ['VCC', 'OUT', 'GND'], properties: { temperature: 25 } },
   photoresistor: { pins: ['VCC', 'AO', 'GND'], properties: { lux: 500 } },
+  // Same physical part as `photoresistor`, exposed under the alias metadataId
+  // the components-metadata generator emits. The SPICE mapper for both is
+  // identical (componentToSpice.ts:MAPPERS['photoresistor-sensor'] = MAPPERS['photoresistor']).
+  'photoresistor-sensor': { pins: ['VCC', 'AO', 'GND'], properties: { lux: 500 } },
   'instr-voltmeter': { pins: ['V+', 'V-'] },
   'instr-ammeter': { pins: ['A+', 'A-'] },
   // Logic gates drive Y via a B-source. Drive inputs to VCC (high), observe