feat(obs): unify metrics initialization and fix exporter move error (#851)

* feat(obs): unify metrics initialization and fix exporter move error

- Fix Rust E0382 (use after move) by removing duplicate MetricExporter consumption.
- Consolidate MeterProvider construction into single Recorder builder path.
- Remove redundant Recorder::builder(...).install_global() call.
- Ensure PeriodicReader setup is performed only once (HTTP + optional stdout).
- Set global meter provider and metrics recorder exactly once.
- Preserve existing behavior for stdout/file vs HTTP modes.
- Minor cleanup: consistent resource reuse and interval handling.

* update telemetry.rs

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* fix

* fix

* fix

* fix: modify logger level from error to event

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

crates/obs/src/lib.rs

@@ -54,13 +54,17 @@
 /// # }
 /// ```
 mod config;
+mod error;
 mod global;
 mod metrics;
+mod recorder;
 mod system;
 mod telemetry;
 
 pub use config::*;
+pub use error::*;
 pub use global::*;
 pub use metrics::*;
+pub use recorder::*;
 pub use system::SystemObserver;
-pub use telemetry::{OtelGuard, TelemetryError};
+pub use telemetry::OtelGuard;