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_admin_users.rs

@@ -381,10 +381,11 @@ async fn delete_writes_audit_row(pool: PgPool) {
         .unwrap();
     assert_eq!(resp.status(), StatusCode::NO_CONTENT);
 
-    let rows: Vec<(Option<Uuid>, String, String, Option<Uuid>, serde_json::Value)> =
-        sqlx::query_as(
-            "SELECT actor_user_id, action, target_kind, target_id, payload FROM admin_audit",
-        )
+    // (actor_user_id, action, target_kind, target_id, payload)
+    type AuditRow = (Option<Uuid>, String, String, Option<Uuid>, serde_json::Value);
+    let rows: Vec<AuditRow> = sqlx::query_as(
+        "SELECT actor_user_id, action, target_kind, target_id, payload FROM admin_audit",
+    )
         .fetch_all(&pool)
         .await
         .unwrap();