feat(07-02): wire AzureAuthToggle tooltipText + add SFTP auth-method tooltip

- AzureAuthToggle reads sas_url/key tooltipText from BACKEND_REGISTRY and passes to PasswordField
- SftpAuthToggle adds showAuthTip state with ⓘ button above segmented control
- All 159 tests pass including UX-01 tooltip toggle tests

src/components/wizard/AzureAuthToggle.tsx

@@ -1,6 +1,7 @@
 import { useState } from 'react';
 import type { UseFormRegister, FieldError } from 'react-hook-form';
 import { PasswordField } from '../ui/PasswordField';
+import { BACKEND_REGISTRY } from '../../schemas/registry';
 
 type AuthMethod = 'sas' | 'key';
 
@@ -15,6 +16,9 @@ interface AzureAuthToggleProps {
 export function AzureAuthToggle({ register, errors }: AzureAuthToggleProps) {
   const [authMethod, setAuthMethod] = useState<AuthMethod>('sas');
 
+  const sasUrlTooltip = BACKEND_REGISTRY.azureblob.fields.find(f => f.key === 'sas_url')?.tooltipText;
+  const keyTooltip = BACKEND_REGISTRY.azureblob.fields.find(f => f.key === 'key')?.tooltipText;
+
   return (
     <div className="flex flex-col gap-3">
       {/* Segmented control */}
@@ -54,6 +58,7 @@ export function AzureAuthToggle({ register, errors }: AzureAuthToggleProps) {
           registration={register('sas_url')}
           placeholder="https://mystorageaccount.blob.core.windows.net/?sv=..."
           helpText="Full SAS URL including account and container"
+          tooltipText={sasUrlTooltip}
         />
       </div>
       <div className={authMethod === 'key' ? 'block' : 'hidden'}>
@@ -63,6 +68,7 @@ export function AzureAuthToggle({ register, errors }: AzureAuthToggleProps) {
           error={errors.key}
           registration={register('key')}
           helpText="Base64-encoded storage account key"
+          tooltipText={keyTooltip}
         />
       </div>
     </div>

src/components/wizard/SftpAuthToggle.tsx

@@ -14,9 +14,29 @@ interface SftpAuthToggleProps {
 
 export function SftpAuthToggle({ register, errors }: SftpAuthToggleProps) {
   const [authMethod, setAuthMethod] = useState<AuthMethod>('password');
+  const [showAuthTip, setShowAuthTip] = useState(false);
 
   return (
     <div className="flex flex-col gap-3">
+      {/* Auth method label + ⓘ button */}
+      <div className="flex items-center gap-1">
+        <span className="text-sm font-medium text-gray-700">Authentication Method</span>
+        <button
+          type="button"
+          onClick={() => setShowAuthTip(v => !v)}
+          aria-label="More info about authentication methods"
+          className="text-blue-500 hover:text-blue-700 text-xs leading-none"
+        >
+          ⓘ
+        </button>
+      </div>
+      {showAuthTip && (
+        <p className="text-xs text-blue-700 bg-blue-50 border border-blue-200 rounded px-2 py-1.5 mt-1">
+          Password auth sends your password to the SFTP server on each connection.
+          Key-based auth uses a private key (more secure — the server only stores your public key).
+          Paste the full private key PEM content (including the -----BEGIN/END----- lines) if using key-based auth.
+        </p>
+      )}
       {/* Segmented control */}
       <div className="flex rounded-md border border-gray-300 overflow-hidden">
         <button