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-config/src/lib.rs

@@ -51,9 +51,8 @@ pub use loader::ConfigLoader;
 
 #[cfg(feature = "validation")]
 pub use validate::{
-    collect_failures, validate_non_empty, validate_port, validate_range,
-    validate_url, ConfigValidator, ConfigValidatorExt, ValidationError,
-    ValidationFailure,
+    collect_failures, validate_non_empty, validate_port, validate_range, validate_url,
+    ConfigValidator, ConfigValidatorExt, ValidationError, ValidationFailure,
 };
 
 #[cfg(feature = "hot-reload")]

crates/mytheclipse-config/src/validate.rs

@@ -33,7 +33,11 @@ pub struct ValidationError {
 
 impl fmt::Display for ValidationError {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "config validation failed ({} issue(s)):", self.failures.len())?;
+        write!(
+            f,
+            "config validation failed ({} issue(s)):",
+            self.failures.len()
+        )?;
         for failure in &self.failures {
             write!(f, "\n  - {failure}")?;
         }
@@ -91,7 +95,11 @@ pub fn validate_url(path: &str, value: &str) -> Option<ValidationFailure> {
     }
     // Minimal heuristic: scheme + host. We avoid pulling in a full URL crate
     // to keep the dependency surface small.
-    let scheme_len = if value.starts_with("http://") { 7 } else if value.starts_with("https://") { 8 } else {
+    let scheme_len = if value.starts_with("http://") {
+        7
+    } else if value.starts_with("https://") {
+        8
+    } else {
         return Some(ValidationFailure {
             path: path.to_string(),
             message: format!("url must start with http:// or https:// (got {value:?})"),
@@ -148,7 +156,9 @@ where
 }
 
 /// Collects all failures from an iterator of `Option<ValidationFailure>`.
-pub fn collect_failures(opts: impl IntoIterator<Item = Option<ValidationFailure>>) -> Result<(), ValidationError> {
+pub fn collect_failures(
+    opts: impl IntoIterator<Item = Option<ValidationFailure>>,
+) -> Result<(), ValidationError> {
     let failures: Vec<_> = opts.into_iter().flatten().collect();
     if failures.is_empty() {
         Ok(())
@@ -186,7 +196,11 @@ mod tests {
 
     #[test]
     fn collect_failures_aggregates_all() {
-        let opts = [validate_non_empty("a", ""), validate_non_empty("b", "ok"), validate_url("c.d", "bad://x")];
+        let opts = [
+            validate_non_empty("a", ""),
+            validate_non_empty("b", "ok"),
+            validate_url("c.d", "bad://x"),
+        ];
         let err = collect_failures(opts).unwrap_err();
         assert_eq!(err.failures.len(), 2);
         assert_eq!(err.failures[0].path, "a");
@@ -195,7 +209,10 @@ mod tests {
 
     #[test]
     fn collect_failures_ok_when_all_pass() {
-        let opts = [validate_url("a", "https://ok.com"), validate_port("b", 8080)];
+        let opts = [
+            validate_url("a", "https://ok.com"),
+            validate_port("b", 8080),
+        ];
         assert!(collect_failures(opts).is_ok());
     }
 
@@ -205,7 +222,10 @@ mod tests {
         impl ConfigValidator for Cfg {
             fn validate(&self) -> Result<(), ValidationError> {
                 Err(ValidationError {
-                    failures: vec![ValidationFailure { path: "x".into(), message: "bad".into() }],
+                    failures: vec![ValidationFailure {
+                        path: "x".into(),
+                        message: "bad".into(),
+                    }],
                 })
             }
         }