fix: accessibility improvements and test infrastructure hardening

Add aria-labels to form controls (selects, checkboxes, switches), set
html lang attribute and page title, fix color contrast for --candle-dim
and --text-faint tokens, underline inline links, remove opacity hack.
Harden dev login endpoints with atomic findOneAndUpdate and tokenVersion
in JWT. Update Playwright timeouts and E2E test helpers.

server/api/dev/member-login.get.js

@@ -25,7 +25,7 @@ export default defineEventHandler(async (event) => {
 
   const config = useRuntimeConfig(event)
   const token = jwt.sign(
-    { memberId: member._id, email: member.email },
+    { memberId: member._id, email: member.email, tv: member.tokenVersion || 0 },
     config.jwtSecret,
     { expiresIn: '7d' }
   )
@@ -34,6 +34,7 @@ export default defineEventHandler(async (event) => {
     httpOnly: true,
     secure: false,
     sameSite: 'lax',
+    path: '/',
     maxAge: 60 * 60 * 24 * 7,
   })