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/tests/api_mangas.rs

@@ -446,7 +446,7 @@ async fn list_tie_break_orders_equal_keys_by_ascending_id(pool: PgPool) {
 
     // Paginating one row at a time reproduces that exact sequence — no overlap,
     // no gap — which only holds because the id tie-break makes the order total.
-    let paged: Vec<String> = vec![page(1, 0).await, page(1, 1).await, page(1, 2).await]
+    let paged: Vec<String> = [page(1, 0).await, page(1, 1).await, page(1, 2).await]
         .iter()
         .map(|b| b["items"][0]["title"].as_str().unwrap().to_string())
         .collect();