chore: add CI, crate metadata, and crate-level documentation

There was no CI of any kind — no workflows directory at all — despite a full
release pipeline (release.toml, cliff.toml, a maintained CHANGELOG, three
tagged releases). The workflow covers the feature combinations that actually
have distinct behaviour, including a release-profile job: `debug_assert!` is
compiled out there, which is exactly where the validation this branch added
has to hold, and a debug-only suite would never have seen it. Determinism is
checked at RAYON_NUM_THREADS of 1, 2, 4 and 8.

The Justfile gains test/lint/fmt/determinism recipes so the same checks run
locally with one command, and `just ci` runs the lot.

`Cargo.toml` had only name, version and edition, so `cargo publish` would
have been rejected. Added description, repository, readme, keywords,
categories, exclude, and `rust-version = "1.85"` — the edition-2024 floor,
now verified by a CI job. Two let-chains introduced earlier on this branch
would have pushed that to 1.88; they are rewritten to keep the floor where
it was.

`src/lib.rs` had no `//!` header at all, so the docs.rs landing page would
have been a bare symbol list — conspicuous given every other module has one.
It now explains what Through Time does differently, and carries three
runnable examples (which `cargo test --doc` checks, where previously there
was nothing to check), including the draw/p_draw interaction that is the
easiest way to get an error out of this crate.

`cargo publish --dry-run` now packages and verifies cleanly. The only
remaining blocker is `license`, which is yours to choose — noted as a TODO
in the manifest rather than picked unilaterally.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DnsaJg74eNSva3PJjK2eej

src/history.rs

@@ -578,10 +578,12 @@ impl<T: Time, D: Drift<T>, O: Observer<T>, K: Eq + Hash + Clone> History<T, D, O
         // than going through `Outcome`.
         if self.p_draw == 0.0 {
             for (event_results, kind) in results.iter().zip(kinds.iter()) {
-                if matches!(kind, EventKind::Ranked)
-                    && let Some(tied) = crate::first_tied_output(event_results)
-                {
-                    return Err(InferenceError::TieWithoutDrawProbability { teams: tied });
+                if !matches!(kind, EventKind::Ranked) {
+                    continue;
+                }
+
+                if let Some(teams) = crate::first_tied_output(event_results) {
+                    return Err(InferenceError::TieWithoutDrawProbability { teams });
                 }
             }
         }