Add reliability enhancements, reachability pre-check, and AT presets

High-impact reliability:
- SQLite job persistence (rv50x.db) — job history and AT sessions survive restarts
- Extract _login_and_open_modal() — eliminates ~40 lines of duplicated Playwright login logic
- Separate NocoDB view IDs per group via NOCODB_VIEW_ID_ELECTRIC / NOCODB_VIEW_ID_GW env vars
- Excel cache TTL (1h) + size cap (20 files) with eviction helpers
- In-memory job store pruning (MAX_JOBS_MEMORY, default 200)

Functionality:
- TCP reachability pre-check before launching Playwright — fails fast on unreachable devices
- AT command presets — save/load/delete named command sequences, stored in at_presets.json

Ops:
- Bind-mount rv50x.db and at_presets.json in docker-compose so data survives rebuilds
- Add NOCODB_VIEW_ID_ELECTRIC, NOCODB_VIEW_ID_GW, REACH_TIMEOUT env vars to compose
- Ignore runtime files (rv50x.db, at_presets.json, template dirs) in .gitignore

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docker-compose.yml

@@ -35,6 +35,8 @@ services:
       - /opt/rv50x-manager/template_uploads:/data/template_uploads
       - /opt/rv50x-manager/xml_templates:/data/xml_templates
       - /opt/rv50x-manager/certs:/certs:ro   # SSL certificates (read-only)
+      - /opt/rv50x-manager/rv50x.db:/app/rv50x.db          # job history (SQLite)
+      - /opt/rv50x-manager/at_presets.json:/app/at_presets.json  # AT presets
     environment:
       # ── NocoDB connection ──────────────────────────────────────────────
       # To use the built-in NocoDB from this stack, set NOCODB_URL to:
@@ -44,7 +46,9 @@ services:
       NOCODB_TOKEN:    ${NOCODB_TOKEN}
       NOCODB_BASE_ID:  ${NOCODB_BASE_ID}
       NOCODB_TABLE_ID: ${NOCODB_TABLE_ID}
-      NOCODB_VIEW_ID:  ${NOCODB_VIEW_ID}
+      NOCODB_VIEW_ID:          ${NOCODB_VIEW_ID}
+      NOCODB_VIEW_ID_ELECTRIC: ${NOCODB_VIEW_ID_ELECTRIC:-}
+      NOCODB_VIEW_ID_GW:       ${NOCODB_VIEW_ID_GW:-}
       # ── SSL certificate paths (inside the container) ───────────────────
       SSL_CERT: /certs/cert.pem
       SSL_KEY:  /certs/key.pem