fix(ci): restore full CI green — test-matrix, clippy, rustfmt, and rustdoc gates

Root cause of the failing CI run was that examples/tests referencing
feature-gated items were auto-detected (no required-features), so
`--all-targets` compiled them under feature combinations where those
modules didn't exist. Fixes:

- mytheclipse Cargo.toml: declare the `high_level` example and
  `race_stress` integration test with required-features = ["full"];
  `cargo build --all-targets` now skips them when full is off. This
  clears the whole test-matrix (workspace default, all-features, and
  every single-feature config) which all failed on E0432/E0433.
- lib.rs: auto_metrics_service depends on service_builder, so regate it
  behind all(observability, resiliency) instead of observability alone
  (observability-only build compiled the module without resiliency).
- mytheclipse-tracing: gate `pub mod fmt` behind any
  tracing-subscriber-providing feature so --no-default-features compiles.
- mytheclipse-queue: gate `pub mod worker` behind in-memory (worker.rs
  requires tokio, only provided by in-memory).
- clippy -D warnings fixes: deprecated base64 0.22 free fns -> Engine
  (paseto), unused key field, needless mut (service_builder), unused
  import/dead var/missing is_empty (bg_join), dead is_expired (dlock),
  while-let-iterator->for (parallel_map), type_complexity (shutdown_guard),
  MutexGuard held across await (middleware, now clones Arc'd layers),
  if-let-Err->is_err (queue), unused CliBuilder fields now wired into clap.
- rustdoc -D warnings: resolve retry/MetricsBridge/CircuitBreaker/KeyRing
  intra-doc links and fix the unparseable lifecycle.rs code fence.
- cargo fmt --all to satisfy the Rustfmt gate.

crates/mytheclipse-queue/src/worker.rs

@@ -71,10 +71,13 @@ pub struct WorkerPool<Q: Queue + 'static> {
 impl<Q: Queue + 'static> WorkerPool<Q> {
     /// Creates a new worker pool with the given concurrency.
     pub fn new(queue: Q, concurrency: usize) -> Self {
-        Self::with_config(queue, WorkerConfig {
-            concurrency,
-            ..Default::default()
-        })
+        Self::with_config(
+            queue,
+            WorkerConfig {
+                concurrency,
+                ..Default::default()
+            },
+        )
     }
 
     /// Creates a new worker pool with explicit configuration.
@@ -148,8 +151,8 @@ impl<Q: Queue + 'static> WorkerPool<Q> {
 /// Computes the (capped) exponential backoff delay.
 pub fn retry_delay(config: &WorkerConfig, attempt: u32) -> Duration {
     let exponent = attempt as f64;
-    let computed = config.retry_base_delay.as_millis() as f64
-        * config.retry_factor.powf(exponent.max(0.0));
+    let computed =
+        config.retry_base_delay.as_millis() as f64 * config.retry_factor.powf(exponent.max(0.0));
     let capped = computed.min(config.retry_max_delay.as_millis() as f64);
     Duration::from_millis(capped as u64)
 }