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-data/src/github_search.rs

@@ -26,11 +26,7 @@ use serde_json::Value;
 use tracing::{debug, warn};
 
 const SOURCE_NAME: &str = "github-search";
-const USER_AGENT: &str = concat!(
-    "moments/",
-    env!("CARGO_PKG_VERSION"),
-    " (+https://rob.tn)"
-);
+const USER_AGENT: &str = concat!("moments/", env!("CARGO_PKG_VERSION"), " (+https://rob.tn)");
 
 #[derive(Clone, Debug)]
 pub struct GithubSearchConfig {
@@ -378,7 +374,10 @@ mod tests {
             "repository": { "full_name": "faith1337z/Trade", "private": false }
         });
         let ev = parse_commit_event(&raw).expect("parses");
-        assert_eq!(ev.id, "github-commit:a6fcefbe909a97ad5a049b9fa48bc74309af10d9");
+        assert_eq!(
+            ev.id,
+            "github-commit:a6fcefbe909a97ad5a049b9fa48bc74309af10d9"
+        );
         assert_eq!(ev.action, "Commit");
         assert!(ev.public);
     }