feat(maestro): orchestra-themed session-name generator (#23)

New shared `maestro-names` crate producing `adjective-instrument` session
handles drawn from the orchestra pit — musical tempo/dynamics/articulation
markings × instruments and forms (e.g. `allegro-cello`, `crescendo-oboe`,
`staccato-viola`), tying handles to the app's conductor metaphor.

- Pure generation takes an injected RNG; no thread_rng/clock in pure paths,
  so seeded tests are reproducible (repo invariant).
- `generate_unique` prefers the bare name, appending an incrementing numeric
  suffix (`-2`, `-3`, …) only on collision via an injected `is_taken`.
- `generate_thread` is the one impure convenience wrapper for runtime callers.
- Wordlists are public so the web UI can mirror them for instant reroll; the
  Rust generator stays the source of truth.

Closes #23. Part of #21 (spawn dialog rework).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Cargo.toml

@@ -19,6 +19,7 @@ futures-util = { version = "0.3", default-features = false, features = ["sink",
 jsonwebtoken = { version = "9", default-features = false }
 libc = "0.2"
 maestro-config = { path = "crates/maestro-config" }
+maestro-names = { path = "crates/maestro-names" }
 maestro-protocol = { path = "crates/maestro-protocol" }
 maestro-tui = { path = "crates/maestro-tui" }
 nix = { version = "0.29", default-features = false, features = ["term", "signal"] }