feat(telemetry): switch to SendForModule, drop hand-bumped Version

Replaces the hand-bumped client.Version="0.7.11" with
telemetry.SendForModule which reads the actual module version from
runtime/debug.BuildInfo.Deps at the consumer's build time. This
means future releases (v0.7.12, v0.8.0, …) will be reported by the
running bot WITHOUT requiring a manual edit of client/version.go on
every tag — consumers just `go get -u` and rebuild.

client.Version is preserved as a fallback for replace directives /
detached `go run`, and remains overridable via -ldflags.

Bumps oss-telemetry to v0.2.1.

client/version.go

@@ -1,12 +1,11 @@
 package client
 
-// Version is the released version of the go-telegram library. Keep in sync
-// with the most recent git tag; this constant is bumped manually on each
-// release. Exposed as a var (not const) so downstream applications may
-// override it via linker flags:
+// Version is a fallback version string used only when Go's build info is
+// unavailable (replace directives, detached `go run`) or has been overridden
+// via linker flags. The authoritative version forwarded to telemetry is
+// resolved at runtime by [telemetry.SendForModule] from the build info of
+// whatever binary linked this library, so this constant does NOT need to be
+// bumped on every release. Exposed as a var (not const) for ldflag override:
 //
 //	go build -ldflags="-X github.com/lukaszraczylo/go-telegram/client.Version=1.2.3"
-//
-// The value is also forwarded as the version field of the anonymous usage
-// ping that fires on the first call to New (see fireTelemetryOnce).
-var Version = "0.7.11"
+var Version = "0.0.0-fallback"