fix(frontend): Sprint 2b — dead code, accessibility, Viewer robustness, ApiError

- Delete unused AdminNav.tsx (dead code)
- Fix RetroTextarea accessibility (useId + htmlFor linkage)
- Fix Viewer.tsx: add open-failed handler, prevent handler accumulation
- Add ApiError class with status code for structured error handling
- Replace fragile msg.includes('404') with ApiError.status check in Reader/Editor

https://claude.ai/code/session_012NCh8yLxMXkRmBYQgHCTik

frontend/src/components/AdminNav.tsx

@@ -1,13 +0,0 @@
-import { RetroButton } from './retro'
-
-interface AdminNavProps {
-  onClick: () => void
-}
-
-export default function AdminNav({ onClick }: AdminNavProps) {
-  return (
-    <RetroButton size="sm" onClick={onClick}>
-      Admin
-    </RetroButton>
-  )
-}

frontend/src/components/Viewer.tsx

@@ -45,6 +45,10 @@ const Viewer: FC<Props> = ({ iiifServiceUrl, fallbackImageUrl, onViewerReady })
     const viewer = viewerRef.current
     if (!viewer || !source) return
 
+    // Remove previous handlers to avoid accumulation on rapid page changes
+    viewer.removeAllHandlers('open')
+    viewer.removeAllHandlers('open-failed')
+
     if (iiifServiceUrl) {
       // Zoom tuilé natif — OpenSeadragon fetch info.json et configure les tuiles
       viewer.open(iiifServiceUrl + '/info.json')
@@ -56,6 +60,10 @@ const Viewer: FC<Props> = ({ iiifServiceUrl, fallbackImageUrl, onViewerReady })
     viewer.addOnceHandler('open', () => {
       onViewerReadyRef.current?.(viewer)
     })
+
+    viewer.addOnceHandler('open-failed', () => {
+      console.warn('[Viewer] Failed to open image source:', source)
+    })
   }, [source, iiifServiceUrl])
 
   return (

frontend/src/components/retro/RetroTextarea.tsx

@@ -1,4 +1,4 @@
-import type { TextareaHTMLAttributes } from 'react'
+import { useId, type TextareaHTMLAttributes } from 'react'
 
 interface Props extends TextareaHTMLAttributes<HTMLTextAreaElement> {
   /** Optional label rendered above the textarea */
@@ -6,14 +6,16 @@ interface Props extends TextareaHTMLAttributes<HTMLTextAreaElement> {
 }
 
 export default function RetroTextarea({ label, className = '', ...rest }: Props) {
+  const id = useId()
   return (
     <div className="flex flex-col gap-[2px]">
       {label && (
-        <label className="text-retro-xs font-retro font-medium text-retro-black">
+        <label htmlFor={id} className="text-retro-xs font-retro font-medium text-retro-black">
           {label}
         </label>
       )}
       <textarea
+        id={id}
         className={`
           px-2 py-[3px]
           text-retro-sm font-retro

frontend/src/lib/api.ts

@@ -188,6 +188,17 @@ export interface CorpusProfile {
   export_config: { mets: boolean; alto: boolean; tei: boolean }
 }
 
+// ── Errors ────────────────────────────────────────────────────────────────────
+
+export class ApiError extends Error {
+  status: number
+  constructor(status: number, message: string) {
+    super(message)
+    this.name = 'ApiError'
+    this.status = status
+  }
+}
+
 // ── Fetch helpers ─────────────────────────────────────────────────────────────
 
 /**
@@ -214,7 +225,7 @@ function extractDetail(payload: unknown, fallback: string): string {
 
 async function get<T>(path: string): Promise<T> {
   const resp = await fetch(`${BASE_URL}${path}`)
-  if (!resp.ok) throw new Error(`HTTP ${resp.status} — ${path}`)
+  if (!resp.ok) throw new ApiError(resp.status, `HTTP ${resp.status} — ${path}`)
   return resp.json() as Promise<T>
 }
 

frontend/src/pages/Editor.tsx

@@ -4,6 +4,7 @@ import {
   applyCorrections,
   getHistory,
   fetchMasterJson,
+  ApiError,
   type PageMaster,
   type VersionInfo,
 } from '../lib/api.ts'
@@ -67,11 +68,11 @@ export default function Editor() {
       const ext = m.extensions as { region_validations?: Record<string, string> } | undefined
       setRegionValidations(ext?.region_validations ?? {})
     } catch (e: unknown) {
-      const msg = (e as Error).message ?? ''
-      if (msg.includes('404')) {
+      if (e instanceof ApiError && e.status === 404) {
         setError('Cette page n\'a pas encore ete analysee par l\'IA. Lancez le pipeline depuis Administration.')
       } else {
-        setError(msg)
+        const msg = e instanceof Error ? e.message : ''
+        setError(msg || 'Erreur de chargement')
       }
     } finally {
       setLoading(false)

frontend/src/pages/Reader.tsx

@@ -5,6 +5,7 @@ import {
   fetchPages,
   fetchMasterJson,
   fetchProfile,
+  ApiError,
   type Page,
   type PageMaster,
   type CorpusProfile,
@@ -63,10 +64,10 @@ export default function Reader() {
       .then(setMaster)
       .catch((e: unknown) => {
         // 404 = page non analysée (normal), autres erreurs = problème réseau
-        const msg = e instanceof Error ? e.message : ''
-        if (msg.includes('404')) {
+        if (e instanceof ApiError && e.status === 404) {
           setMaster(null)
         } else {
+          const msg = e instanceof Error ? e.message : ''
           setMasterError(msg || 'Erreur de chargement')
         }
       })