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-crypto/src/key_registry.rs

@@ -1,6 +1,6 @@
 //! Typed key registry with ID-based lookup (feature `password`).
 //!
-//! [`TypedKeyRegistry`] extends [`KeyRing`] semantics: instead of a single
+//! [`TypedKeyRegistry`] extends `KeyRing` semantics: instead of a single
 //! current+previous sequence, it maintains a map of named keys keyed by an ID,
 //! with one designated "current" ID. This is useful when keys are rotated by ID
 //! (e.g. JWT `kid` header) and you need to look up a verification key by ID
@@ -20,7 +20,10 @@ pub struct TypedKeyRegistry<T> {
 impl<T> TypedKeyRegistry<T> {
     /// Creates an empty registry (no current key).
     pub fn new() -> Self {
-        Self { keys: HashMap::new(), current_id: None }
+        Self {
+            keys: HashMap::new(),
+            current_id: None,
+        }
     }
 
     /// Registers a key under `id`, making it the current key.
@@ -37,9 +40,7 @@ impl<T> TypedKeyRegistry<T> {
 
     /// Returns the current key, if any.
     pub fn current(&self) -> Option<&T> {
-        self.current_id
-            .as_ref()
-            .and_then(|id| self.keys.get(id))
+        self.current_id.as_ref().and_then(|id| self.keys.get(id))
     }
 
     /// Returns the ID of the current key.