feat(5.20): US-004/005/006/009 ingestie+API+worker+import pe mediu RAR

US-004: rezolva_rar_env (cerere>default cont>ancora globala) + MediuIndisponibil
+ cod RAR_MEDIU_INDISPONIBIL.
US-005: camp rar_env pe POST /v1/prezentari + /valideaza (Literal), echo in
SubmissionResult/ValidareResult/GET, build_key + INSERT env-aware.
US-006: AccountSessions re-cheiat (account_id, rar_env); RarClient base_url per
env; creds din slotul env; purge + recover_orphans scoped pe env (E1/1a, 1b/E6);
claim_one propaga rar_env (1c/E8); keepalive pe ancora globala (M2).
US-009: selector mediu la import (>=2 medii), eticheta la 1, banner la 0; commit
seteaza rar_env pe submissions.

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

app/web/templates/_preview_import.html

@@ -14,6 +14,14 @@
         Preview —
         <span class="muted" style="font-weight:400;">{{ filename or ("import #" ~ import_id) }}</span>
       </h2>
+      {# Badge mediu RAR (US-009): vizibil intotdeauna in preview (claritate tinta) #}
+      {% if rar_env %}
+      <span class="pill" style="font-size:var(--fs-xs);
+            {% if rar_env == 'prod' %}background:color-mix(in srgb,#B4452F 15%,var(--card)); border-color:#B4452F; color:#B4452F; font-weight:700;
+            {% else %}background:color-mix(in srgb,var(--accent) 12%,var(--card)); border-color:var(--accent); color:var(--accent);{% endif %}">
+        {{ "PRODUCTIE" if rar_env == "prod" else "Testare" }}
+      </span>
+      {% endif %}
       <span class="muted" style="margin-left:auto; font-size:var(--fs-sm);">{{ total }} randuri</span>
     </div>
 
@@ -178,6 +186,8 @@
           hx-target="#import-section"
           hx-swap="outerHTML">
       <input type="hidden" name="csrf_token" value="{{ csrf_token or '' }}">
+      {# Mediu RAR ales la upload — propagar la commit (US-009) #}
+      <input type="hidden" name="rar_env" value="{{ rar_env or '' }}">
       <div class="sticky-bar">
         <div style="flex:1; min-width:280px;">
           <!-- Banner declarant — direct deasupra input-ului N -->