refactor(clippy): fix the never-loop error and clear all lint warnings

`cargo clippy --all-targets` was failing on a deny-by-default
`never_loop` in the analysis SSE handler (the `loop` always returned on
the first iteration — the stream `unfold` already re-enters per event),
plus ~28 warnings. All resolved with no behaviour change:

- admin/analysis SSE: drop the dead `loop` wrapper.
- app: match port literals directly instead of `if p == 80` guards.
- repo/user: separate doc list from the following paragraphs.
- repo/upload_history: `sort_by_key(Reverse(..))` over `sort_by`.
- crawler/nav test: construct the error directly (no `unwrap_err` on a
  literal `Err`).
- test helpers: build configs via struct-update syntax instead of
  `Default::default()` + field reassignment; add a type alias for a
  complex audit-row tuple.
- plus the mechanical `deref`/etc. fixes from `cargo clippy --fix`.

Note: not running `cargo fmt` — the backend uses a consistent
hand-formatted style that differs from rustfmt-default across ~110
files, so a blanket reformat would be pure churn.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/src/api/mangas.rs

@@ -255,8 +255,8 @@ async fn create(
     )
     .await?;
 
-    let author_refs = repo::author::set_for_manga(&mut *tx, manga.id, &authors).await?;
-    repo::genre::set_for_manga(&mut *tx, manga.id, &metadata.genre_ids).await?;
+    let author_refs = repo::author::set_for_manga(&mut tx, manga.id, &authors).await?;
+    repo::genre::set_for_manga(&mut tx, manga.id, &metadata.genre_ids).await?;
 
     if let Some(img) = cover {
         let key = format!("mangas/{}/cover.{}", manga.id, img.ext);
@@ -321,7 +321,7 @@ async fn update(
 
     let mut tx = state.db.begin().await?;
     let _updated = repo::manga::update_basics(
-        &mut *tx,
+        &mut tx,
         id,
         patch.title.as_deref().map(str::trim),
         patch.status.as_deref().map(str::trim),
@@ -331,10 +331,10 @@ async fn update(
     )
     .await?;
     if let Some(ref names) = authors_owned {
-        repo::author::set_for_manga(&mut *tx, id, names).await?;
+        repo::author::set_for_manga(&mut tx, id, names).await?;
     }
     if let Some(ref ids) = patch.genre_ids {
-        repo::genre::set_for_manga(&mut *tx, id, ids).await?;
+        repo::genre::set_for_manga(&mut tx, id, ids).await?;
     }
     tx.commit().await?;