chore(deps): rand 0.9.4 + compatible sweep + serde_yaml→serde_norway (#966)

Focused Rust dependency-maintenance pass from the 2026-05-23 security/freshness
review. No CVEs; one advisory cleared and one deprecated crate replaced.

- rand 0.9.2 → 0.9.4 (lockfile): clears RUSTSEC-2026-0097 (unsound with a
  custom logger using rand::rng()). Semver-compatible; rand 0.10 is a separate
  major.
- Compatible-update sweep: ~90 lockfile-only patch/minor bumps (bevy 0.18.0→
  0.18.1, clap 4.5→4.6, rayon 1.11→1.12, pathfinding 4.14→4.15, uuid 1.20→1.23,
  zerocopy, serde_json, tracing-subscriber, etc.). cargo test green.
- serde_yaml 0.9 (deprecated/archived upstream) → serde_norway 0.9, an actively
  maintained drop-in fork. In the server it is test-only (poi.rs round-trip,
  trait_modifiers.rs fixture, tests/news_ticker.rs) so it moves to
  dev-dependencies; line-previewer parses dialogue/monologue pool YAML at
  runtime, so it keeps it as a normal dependency. API is identical (from_str/
  to_string).

news_ticker.rs also picks up its share of the #967 clippy sweep (HashSet/HashMap
→ BTree, doc-list indent) since it is the same file as the serde rename.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

server/Cargo.toml

@@ -14,7 +14,6 @@ bevy_tasks = { version = "0.18", features = ["multi_threaded"] }
 # systems marked with TODO comments. Active use begins when profiling shows bottlenecks.
 rayon = "1"
 serde = { version = "1", features = ["derive"] }
-serde_yaml = "0.9"
 ron = "0.8"
 rmp-serde = "1"
 rand = "0.9"
@@ -40,6 +39,9 @@ default = ["gauntlet"]
 gauntlet = []
 
 [dev-dependencies]
+# Maintained drop-in fork of the deprecated serde_yaml 0.9 (#966). Test-only:
+# the YAML round-trip in poi.rs and the trait-config fixture in trait_modifiers.rs.
+serde_norway = "0.9"
 
 # ---------------------------------------------------------------------------
 # Explicit test target for the Layer 3 integration module (D-030, ticket #200).