v3: error cards across the app, friendly network errors, code quality pass

src/pages/Dump.tsx

@@ -22,6 +22,7 @@ import { PageShell } from "../components/PageShell.tsx";
 import { PageError } from "../components/PageError.tsx";
 import { Markdown } from "../components/Markdown.tsx";
 import { CommentThread } from "../components/CommentThread.tsx";
+import { friendlyFetchError } from "../utils/apiError.ts";
 
 type DumpState =
   | { status: "loading" }
@@ -72,9 +73,10 @@ export function Dump() {
           cache: "no-store",
           headers: token ? { Authorization: `Bearer ${token}` } : {},
         });
-        if (!res.ok) throw new Error(`HTTP ${res.status}`);
-
         const apiResponse = await res.json();
+        if (!apiResponse.success) {
+          throw new Error(apiResponse.error?.message ?? "Failed to load dump");
+        }
         const dump: Dump = deserializeDump(apiResponse.data);
         setDumpState({ status: "loaded", dump });
 
@@ -83,10 +85,7 @@ export function Dump() {
           .then((r) => r.success && setOp(deserializePublicUser(r.data)))
           .catch(() => {});
       } catch (err) {
-        setDumpState({
-          status: "error",
-          error: err instanceof Error ? err.message : "Failed to load dump",
-        });
+        setDumpState({ status: "error", error: friendlyFetchError(err) });
       }
     })();
   }, [selectedDump, preloaded]);