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/cleanup.go

@@ -108,7 +108,7 @@ func (c *Cleaner) findStuckInstallations(ctx context.Context) ([]StuckRecord, er
 
 	req, err := http.NewRequestWithContext(ctx, http.MethodGet,
 		fmt.Sprintf("%s/api/collections/%s/records?filter=%s&perPage=100",
-			c.pb.baseURL, c.pb.devColl, filter),
+			c.pb.baseURL, c.pb.targetColl, filter),
 		nil,
 	)
 	if err != nil {