Add Pi-side upload client for Phase 9 remote server

- app_sql.py: add UPLOADED column + migration on tracking table, add
  settings and dashcam_uploads tables, add helpers for unsent-row
  queries, marking rows uploaded, and dashcam upload dedupe tracking.
- app_upload.py: new background upload client. Periodically batches
  unsent tracking rows to POST /api/v1/tracking/batch and uploads new
  dashcam files (sha256-verified) to POST /api/v1/dashcam/upload, with
  exponential backoff on failure. Exposes get_status() and a
  dashcam-upload enable/disable toggle backed by the settings table.
- app.py: start the upload client thread at startup, add
  GET /api/upload/status and POST /api/upload/dashcam_toggle routes.
- dash.html/dash.js: add a "Remote server upload" card with upload
  status and a toggle switch to pause dashcam video uploads while
  trip/GPS log uploads keep running (per user request - useful on a
  slow/metered connection).
- db/upload_creds.env: new gitignore-exempted template (mirrors
  db/creds.env) for YARIS_SERVER_URL/YARIS_DEVICE_NAME/YARIS_API_KEY.
- requirements.txt: add requests.

Tested against the real deployed unraid server: tracking batch upload
+ dedupe, dashcam upload + dedupe, and toggle-off correctly pausing
dashcam uploads while tracking uploads continue. Also verified the
full Flask app imports/runs cleanly and the new API routes + dash.html
toggle render correctly in a headless browser.

Co-authored-by: Copilot <[email protected]>

templates/dash.html

@@ -68,7 +68,7 @@
                             <button id="dash-import-btn" class="btn btn-primary" type="button" disabled>Import videos</button>
                         </div>
                     </div>
-                    <div class="card shadow">
+                    <div class="card shadow mb-4">
                         <div class="card-header py-3">
                             <p class="text-primary m-0 fw-bold">Import results</p>
                         </div>
@@ -76,6 +76,25 @@
                             <p id="dash-import-status">No import has been run yet.</p>
                         </div>
                     </div>
+                    <div class="card shadow">
+                        <div class="card-header py-3">
+                            <p class="text-primary m-0 fw-bold">Remote server upload</p>
+                        </div>
+                        <div class="card-body">
+                            <p id="upload-status">Checking upload status...</p>
+                            <div class="form-check form-switch">
+                                <input class="form-check-input" type="checkbox" role="switch" id="dashcam-upload-toggle" disabled>
+                                <label class="form-check-label" for="dashcam-upload-toggle">
+                                    Upload dashcam videos to remote server
+                                </label>
+                            </div>
+                            <p class="text-muted small mt-2 mb-0">
+                                Trip/GPS log uploads always stay on. Turning this off only pauses
+                                the (larger) dashcam video uploads - useful on a slow or metered
+                                connection.
+                            </p>
+                        </div>
+                    </div>
                 </div>
             </div>
             <footer class="bg-white sticky-footer">