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/analysis/vision.rs

@@ -1212,14 +1212,16 @@ mod tests {
         // VisionClient pointed at a closed local port. Reqwest fails the
         // POST immediately (connection refused), but the prep work runs
         // before the POST is even built.
-        let mut cfg = AnalysisConfig::default();
-        cfg.endpoint = "http://127.0.0.1:1/v1/chat/completions".into();
-        cfg.model = "stub".into();
-        cfg.request_timeout = Duration::from_secs(1);
-        // Tune slice geometry to match the test image's shape.
-        cfg.max_pixels = 1_000_000;
-        cfg.min_slice_height = 100;
-        cfg.tall_aspect_threshold = 1.8;
+        let cfg = AnalysisConfig {
+            endpoint: "http://127.0.0.1:1/v1/chat/completions".into(),
+            model: "stub".into(),
+            request_timeout: Duration::from_secs(1),
+            // Tune slice geometry to match the test image's shape.
+            max_pixels: 1_000_000,
+            min_slice_height: 100,
+            tall_aspect_threshold: 1.8,
+            ..Default::default()
+        };
         let http = reqwest::Client::builder()
             .timeout(cfg.request_timeout)
             .no_proxy()