fix(a11y): semantic headings, htmlFor/id associations, remove duplicate aria-labels

H-tag: add as=h1/h2 to dialog/UIA/auth headings (21 components)
Label: add htmlFor/id to PasswordRegisterForm (5 pairs) and PasswordResetForm (3 pairs)
Dupe: remove duplicate aria-label from Controls.tsx screenshare button, MembersDrawer, Members, RoomInput

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/pages/auth/reset-password/PasswordResetForm.tsx

@@ -170,12 +170,13 @@ export function PasswordResetForm({ defaultEmail }: PasswordResetFormProps) {
         Homeserver <strong>{server}</strong> will send you an email to let you reset your password.
       </Text>
       <Box direction="Column" gap="100">
-        <Text as="label" size="L400" priority="300">
+        <Text as="label" size="L400" priority="300" htmlFor="emailInput">
           Email
         </Text>
         <Input
           defaultValue={defaultEmail}
           type="email"
+          id="emailInput"
           name="emailInput"
           aria-label="Email address"
           variant="Background"
@@ -193,12 +194,13 @@ export function PasswordResetForm({ defaultEmail }: PasswordResetFormProps) {
         {(match, doMatch, passRef, confPassRef) => (
           <>
             <Box direction="Column" gap="100">
-              <Text as="label" size="L400" priority="300">
+              <Text as="label" size="L400" priority="300" htmlFor="passwordInput">
                 New Password
               </Text>
               <PasswordInput
                 ref={passRef}
                 onChange={doMatch}
+                id="passwordInput"
                 name="passwordInput"
                 aria-label="New password"
                 variant="Background"
@@ -208,12 +210,13 @@ export function PasswordResetForm({ defaultEmail }: PasswordResetFormProps) {
               />
             </Box>
             <Box direction="Column" gap="100">
-              <Text as="label" size="L400" priority="300">
+              <Text as="label" size="L400" priority="300" htmlFor="confirmPasswordInput">
                 Confirm Password
               </Text>
               <PasswordInput
                 ref={confPassRef}
                 onChange={doMatch}
+                id="confirmPasswordInput"
                 name="confirmPasswordInput"
                 aria-label="Confirm new password"
                 variant="Background"