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>

web/static/css/style.css

@@ -68,18 +68,29 @@ nav a {
 nav a:hover { background: rgba(255,255,255,0.1); }
 nav a.active { color: var(--accent-bright); border-bottom: 2px solid var(--accent-bright); }
 
-main { padding: 16px; }
+main { padding: 12px 0; }
 
 .tab-content { display: none; }
 .tab-content.active { display: block; }
 
+.controls, .bg-stats, #isotopes-table, #peaks-table, .history-item, .chart-header {
+    margin-left: 12px;
+    margin-right: 12px;
+}
+
 .chart-container {
     background: var(--bg-card);
     border-radius: 8px;
     padding: 12px;
-    margin-bottom: 12px;
+    margin: 0 12px 12px 12px;
     height: 450px;
+    width: calc(100% - 24px);
     position: relative;
+    overflow: hidden;
+}
+
+.chart-container canvas {
+    display: block;
 }
 
 .controls {