HOTFIX: useMutation.run returns MutationOutcome (no throw); sweep all 7 call sites + README convention

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

gerbil-manager-web/src/pages/BeckenDetailPage.tsx

@@ -42,16 +42,14 @@ export default function BeckenDetailPage() {
   async function onDelete() {
     if (!window.confirm(t.delete.confirmMessage)) return
     setDeleteError(null)
-    try {
-      await removal.run()
+    const result = await removal.run()
+    if (result.ok) {
       navigate('/becken')
-    } catch (err) {
+    } else if (result.cause instanceof ApiError && result.cause.status === 409) {
       // Backend meldet Konflikt, wenn noch Tiere im Becken wohnen.
-      if (err instanceof ApiError && err.status === 409) {
-        setDeleteError(t.delete.conflict)
-      } else {
-        setDeleteError(removal.error ?? de.api.errors.unknown)
-      }
+      setDeleteError(t.delete.conflict)
+    } else {
+      setDeleteError(result.error)
     }
   }
 

gerbil-manager-web/src/pages/BeckenFormPage.tsx

@@ -44,8 +44,9 @@ export default function BeckenFormPage() {
       return
     }
     setErrors({})
-    const saved = await mutation.run({ name: form.name.trim(), notes: nn(form.notes) })
-    navigate(`/becken/${saved.id}`)
+    const result = await mutation.run({ name: form.name.trim(), notes: nn(form.notes) })
+    if (result.ok) navigate(`/becken/${result.value.id}`)
+    // On failure mutation.error drives the inline alert; run() never throws.
   }
 
   if (isEdit && existing.loading) return <p className="muted">{de.common.loading}</p>

gerbil-manager-web/src/pages/GerbilFormPage.tsx

@@ -166,13 +166,9 @@ export default function GerbilFormPage() {
       genotype: nn(form.genotype),
       notes: nn(form.notes),
     }
-    try {
-      const saved = await mutation.run(body)
-      navigate(`/rennmaeuse/${saved.id}`)
-    } catch {
-      // Error is surfaced via mutation.error; swallow so the rejected promise
-      // from this async submit handler doesn't become an unhandled rejection.
-    }
+    const result = await mutation.run(body)
+    if (result.ok) navigate(`/rennmaeuse/${result.value.id}`)
+    // On failure mutation.error drives the inline alert; run() never throws.
   }
 
   if (isEdit && existing.loading) return <p className="muted">{de.common.loading}</p>

gerbil-manager-web/src/pages/KontaktDetailPage.tsx

@@ -45,16 +45,14 @@ export default function KontaktDetailPage() {
   async function onDelete() {
     if (!window.confirm(t.delete.confirmMessage)) return
     setDeleteError(null)
-    try {
-      await removal.run()
+    const result = await removal.run()
+    if (result.ok) {
       navigate('/kontakte')
-    } catch (err) {
+    } else if (result.cause instanceof ApiError && result.cause.status === 409) {
       // Backend meldet Konflikt, wenn der Kontakt noch referenziert wird.
-      if (err instanceof ApiError && err.status === 409) {
-        setDeleteError(t.delete.conflict)
-      } else {
-        setDeleteError(removal.error ?? de.api.errors.unknown)
-      }
+      setDeleteError(t.delete.conflict)
+    } else {
+      setDeleteError(result.error)
     }
   }
 

gerbil-manager-web/src/pages/KontaktFormPage.tsx

@@ -52,12 +52,13 @@ export default function KontaktFormPage() {
       return
     }
     setErrors({})
-    const saved = await mutation.run({
+    const result = await mutation.run({
       name: form.name.trim(),
       contactInfo: nn(form.contactInfo),
       notes: nn(form.notes),
     })
-    navigate(`/kontakte/${saved.id}`)
+    if (result.ok) navigate(`/kontakte/${result.value.id}`)
+    // On failure mutation.error drives the inline alert; run() never throws.
   }
 
   if (isEdit && existing.loading) return <p className="muted">{de.common.loading}</p>

gerbil-manager-web/src/pages/WurfFormPage.tsx

@@ -116,13 +116,9 @@ export default function WurfFormPage() {
       expectedGoHomeDate: nn(form.expectedGoHomeDate),
       notes: nn(form.notes),
     }
-    try {
-      const saved = await mutation.run(body)
-      navigate(`/wuerfe/${saved.id}`)
-    } catch {
-      // Error surfaced via mutation.error; swallow to avoid an unhandled
-      // rejection escaping this async submit handler.
-    }
+    const result = await mutation.run(body)
+    if (result.ok) navigate(`/wuerfe/${result.value.id}`)
+    // On failure mutation.error drives the inline alert; run() never throws.
   }
 
   if (isEdit && existing.loading) return <p className="muted">{de.common.loading}</p>