fix: make the workspace pass the CI lint/test gate

The new Gitea Actions build gate runs `cargo fmt --check`, `clippy -D warnings`,
and `cargo test` — stricter than the old deploy.sh, which only `cargo build`d.
That surfaced pre-existing drift that never compiled under the test/clippy
profile:

- apply rustfmt across the workspace (formatting only, no logic changes)
- moments-data: add the missing `prune_events` to the test-only `NoopWriter`
  stub (the EventWriter trait gained it with the blog-prune feature; a plain
  `cargo build` never compiles the `#[cfg(test)]` stub, so it went stale)
- moments-api: `.max().min()` -> `.clamp()`, and build `usvg::Options` with
  struct-update syntax instead of post-Default field assignment

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01X7zF7Kf4JqDwa6M8Qgge9M

crates/moments-core/src/presentation/hg.rs

@@ -23,10 +23,7 @@ pub(crate) fn reshape(event: &Event) -> TimelineItem {
         .next()
         .unwrap_or("")
         .to_string();
-    let author = p
-        .get("author")
-        .and_then(Value::as_str)
-        .map(author_name);
+    let author = p.get("author").and_then(Value::as_str).map(author_name);
 
     let mut title = Vec::new();
     if let Some(name) = author {