docs(sim): rustdoc backtick-fix for angle-bracketed type names + URL linkify

Three rustdoc warnings (cargo doc --no-deps) in slice-4-half modules:
- latency.rs:55 ('Vec<Capture>' in a heading) — rustdoc parses <Capture> as an HTML tag start.
- scenario.rs:32 (URL with embedded space) — malformed; replaced with the canonical serde.rs URL.
- tick_lag.rs:32 ('Mutex<Vec<Duration>>' in a heading) — same HTML tag-parse issue.

All three fixed by wrapping type expressions in backticks (the rustdoc convention
for inline code) and using a properly-linkified bare URL. No source semantics changed.

Signed-off-by: Aaron D. Lee <himself@adlee.work>

crates/rutster-sim/src/latency.rs

@@ -52,7 +52,7 @@ use crate::sim_audio_pipe::Capture;
 /// # }
 /// ```
 ///
-/// # Why this is a struct (not free fns on Vec<Capture>)
+/// # Why this is a struct (not free fns on `Vec<Capture>`)
 ///
 /// The struct holds the captures by value (one allocation per run, post
 /// the hot path). Free fns would require either passing `&[Capture]`

crates/rutster-sim/src/scenario.rs

@@ -29,7 +29,7 @@
 //! shape for "list of named, differently-shaped records" in TOML — the
 //! alternative (externally-tagged) would require a redundant table layer
 //! (`[[steps]] variant = { speak_loud = { frames = 20 } }`) that hurts
-//! readability for no benefit. See <https://serde.rs enum-representations>.
+//! readability for no benefit. See <https://serde.rs/enum-representations.html>
 //!
 //! `rename_all = "snake_case"` maps the Rust `SpeakLoud` variant to the
 //! TOML `speak_loud` tag — matches the convention used in slice-4's

crates/rutster-sim/src/tick_lag.rs

@@ -29,7 +29,7 @@
 //! `MediaThread` registration (the RegisterSim variant forbidden this
 //! slice) OR a client-server sim mode (deferred per spec §8.6).
 //!
-//! # Hot-path design: atomics (not Mutex<Vec<Duration>>)
+//! # Hot-path design: atomics (not `Mutex<Vec<Duration>>`)
 //!
 //! Per-tick recording is 3 atomic ops:
 //! 1. CAS loop on `max_tick_lag_micros` (atomic max update).