Unify telemetry storage and add repo filtering

Refactor telemetry backend to store all telemetry in a single collection and add repo_source-based filtering.

Key changes:
- Added detect_repo_source() in misc/api.func to auto-detect/export REPO_SOURCE (ProxmoxVE/ProxmoxVED/external) when scripts are sourced.
- Consolidated PocketBase collections into a single default collection (_telemetry_data) across service, migration, and scripts; updated defaults in migrate.go, migration.go, migrate.sh and migration shell scripts.
- Simplified PBClient to use one targetColl and removed collection resolution logic; updated create/update/find/fetch functions to use targetColl.
- Introduced repo_source field (values: "ProxmoxVE", "ProxmoxVED", "external") on telemetry records and telemetry payloads; updated validation and logging.
- Added repo filtering to dashboard endpoints, FetchDashboardData and FetchRecordsPaginated, plus a repo selector in the dashboard UI; default filter is ProxmoxVE (production), with an "all" option.
- Adjusted API handlers and callers to pass repo filters and include repo_source when upserting telemetry.
- Misc: updated comments, error messages, and logging to reflect the new model; added telemetry-service.exe binary.

Purpose: simplify data model (single collection), make telemetry attributable to repository sources, and enable dashboard filtering by repo/source.

misc/data/alerts.go

@@ -134,7 +134,7 @@ func (a *Alerter) checkAndAlert() {
 	defer cancel()
 
 	// Fetch last hour's data
-	data, err := a.pb.FetchDashboardData(ctx, 1)
+	data, err := a.pb.FetchDashboardData(ctx, 1, "ProxmoxVE")
 	if err != nil {
 		log.Printf("WARN: alert check failed: %v", err)
 		return
@@ -410,13 +410,13 @@ func (a *Alerter) fetchWeeklyReportData(ctx context.Context) (*WeeklyReportData,
 	year, week := lastMonday.ISOWeek()
 
 	// Fetch current week's data (7 days)
-	currentData, err := a.pb.FetchDashboardData(ctx, 7)
+	currentData, err := a.pb.FetchDashboardData(ctx, 7, "ProxmoxVE")
 	if err != nil {
 		return nil, fmt.Errorf("failed to fetch current week data: %w", err)
 	}
 
 	// Fetch previous week's data for comparison (14 days, we'll compare)
-	prevData, err := a.pb.FetchDashboardData(ctx, 14)
+	prevData, err := a.pb.FetchDashboardData(ctx, 14, "ProxmoxVE")
 	if err != nil {
 		// Non-fatal, just log
 		log.Printf("WARN: could not fetch previous week data: %v", err)