Fix: CsI(Tl) non-linear response correction + detector calibration overhaul

Root cause of Am-241 misidentification: the Radiacode 103's CsI(Tl) crystal
shifts low-energy peaks upward (59.5 keV → 71.6 keV for Am-241) due to
non-proportional scintillation response. The model was trained on theoretical
peak positions and couldn't match the shifted real peaks.

Changes:
- Add inverse CsI(Tl) non-linear correction to inference pipeline
  (radiacode_monitor.py, web/config.py, test_detection.py)
  E_apparent = E_true * (1 + 0.37 * exp(-E_true/100))
  Corrects channel mapping so peaks appear at theoretical energies
- Fix energy calibration: DetectorConfig now uses E = 0.33 + 2.97*ch
  with 1023 channels, matching the real detector (was energy_min=20,
  skip_first_channel=True, different channel width)
- Add K-escape peaks for CsI(Tl) iodine X-ray escape (E - 28.5 keV)
- Add asymmetric peak shapes for low-energy tails (< 200 keV)
- Add log1p normalization in dataset and inference (replaces max-norm)
- Add background-subtracted training mode (subtract_background flag)
- Add low-signal augmentation (0.01-5 Bq activities, 30-300s durations)
- Update docker-compose.yml: batch_size=32, duration=30-300s,
  CSI_NONLINEAR_ALPHA/BETA env vars for detect and web
- Web dashboard: apply CsI correction to displayed spectra
- Various UI fixes (Chart.js width, zoom/pan, isotope lines)

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

docker-compose.yml

@@ -20,11 +20,11 @@ services:
       - MODEL_DIR=/models
       - NUM_SAMPLES=50000
       - EPOCHS=100
-      - BATCH_SIZE=64
+      - BATCH_SIZE=32
       - LEARNING_RATE=0.001
       - DETECTOR=radiacode_103
-      - MIN_DURATION=43200
-      - MAX_DURATION=86400
+      - MIN_DURATION=30
+      - MAX_DURATION=300
       - SEED=42
       - MEASURED_BACKGROUND_PATH=/data/background_24h.npy
     restart: "no"
@@ -53,6 +53,8 @@ services:
       - REPORT_HOUR=0
       - MIN_LIVE_TIME=3600
       - THRESHOLD=0.5
+      - CSI_NONLINEAR_ALPHA=0.37
+      - CSI_NONLINEAR_BETA=100.0
     restart: unless-stopped
 
   web:
@@ -74,4 +76,6 @@ services:
       - ISOTOPE_INDEX_PATH=/models/vega_isotope_index.txt
       - ENERGY_CALIBRATION_OFFSET=0.33
       - ENERGY_CALIBRATION_SLOPE=2.97
+      - CSI_NONLINEAR_ALPHA=0.37
+      - CSI_NONLINEAR_BETA=100.0
     restart: unless-stopped