Add frontend autoformatting and set CI to require formatted code for all languages (#6052)

# Description of Changes
Changes the strategy for autoformatting to reject PRs if they are not
formatted correctly instead of allowing them to merge and then spawning
a new PR to fix the formatting. The old strategy just caused more work
for us because we'd have to manually approve the followup PR and get it
merged, which required 2 reviewers so in practice it rarely got done and
just meant everyone's PRs ended up containing reformatting for unrelated
files, which makes code review unnecessarily difficult. If the PR's code
is not formatted correctly after this PR, a comment will be added
automatically to tell the author how to run the formatter script to fix
their code so it can go in.

This also enables autoformatting for the frontend code, using Prettier.
I've enabled it for pretty much everything in the frontend folder, other
than 3rd party files and files it doesn't make sense for. I also
excluded Markdown because it sounds likely to be more annoying to have
to autoformat the Markdown in the frontend folder but nowhere else. Open
to changing this though if people disagree.

> [!note]
> 
> Advice to reviewers: The first commit contains all of the actual logic
I've introduced (CI changes, Prettier config, etc.)
> The second commit is just the reformatting of the entire frontend
folder.
> The first commit needs proper review, the second one just give it a
spot-check that it's doing what you'd expect.

frontend/src/saas/components/onboarding/slides/FreeTrialSlide.tsx

@@ -1,8 +1,8 @@
-import React from 'react';
-import { useTranslation } from 'react-i18next';
-import { SlideConfig } from '@app/types/types';
-import { UNIFIED_CIRCLE_CONFIG } from '@app/components/onboarding/slides/unifiedBackgroundConfig';
-import { TrialStatus } from '@app/auth/UseSession';
+import React from "react";
+import { useTranslation } from "react-i18next";
+import { SlideConfig } from "@app/types/types";
+import { UNIFIED_CIRCLE_CONFIG } from "@app/components/onboarding/slides/unifiedBackgroundConfig";
+import { TrialStatus } from "@app/auth/UseSession";
 
 interface FreeTrialSlideProps {
   trialStatus: TrialStatus;
@@ -11,11 +11,7 @@ interface FreeTrialSlideProps {
 function FreeTrialSlideTitle() {
   const { t } = useTranslation();
 
-  return (
-    <span>
-      {t('onboarding.freeTrial.title', 'Your 30-Day Pro Trial')}
-    </span>
-  );
+  return <span>{t("onboarding.freeTrial.title", "Your 30-Day Pro Trial")}</span>;
 }
 
 const FreeTrialSlideBody = ({ trialStatus }: { trialStatus: TrialStatus }) => {
@@ -23,58 +19,60 @@ const FreeTrialSlideBody = ({ trialStatus }: { trialStatus: TrialStatus }) => {
 
   // Format the trial end date
   const trialEndDate = new Date(trialStatus.trialEnd).toLocaleDateString(undefined, {
-    year: 'numeric',
-    month: 'long',
-    day: 'numeric',
+    year: "numeric",
+    month: "long",
+    day: "numeric",
   });
 
   // Determine which message to show based on payment method
   const afterTrialMessage = trialStatus.hasScheduledSub
-    ? t('onboarding.freeTrial.afterTrialWithPayment', 'Your Pro subscription will start automatically when the trial ends.')
+    ? t("onboarding.freeTrial.afterTrialWithPayment", "Your Pro subscription will start automatically when the trial ends.")
     : trialStatus.hasPaymentMethod
-    ? t('onboarding.freeTrial.afterTrialWithPayment', 'Your Pro subscription will start automatically when the trial ends.')
-    : t('onboarding.freeTrial.afterTrialWithoutPayment', 'After your trial ends, you\'ll continue with our free tier. Add a payment method to keep Pro access.');
+      ? t("onboarding.freeTrial.afterTrialWithPayment", "Your Pro subscription will start automatically when the trial ends.")
+      : t(
+          "onboarding.freeTrial.afterTrialWithoutPayment",
+          "After your trial ends, you'll continue with our free tier. Add a payment method to keep Pro access.",
+        );
 
   // Pluralize days remaining
-  const daysText = trialStatus.daysRemaining === 1
-    ? t('onboarding.freeTrial.daysRemainingSingular', '{{days}} day remaining', { days: trialStatus.daysRemaining })
-    : t('onboarding.freeTrial.daysRemaining', '{{days}} days remaining', { days: trialStatus.daysRemaining });
+  const daysText =
+    trialStatus.daysRemaining === 1
+      ? t("onboarding.freeTrial.daysRemainingSingular", "{{days}} day remaining", { days: trialStatus.daysRemaining })
+      : t("onboarding.freeTrial.daysRemaining", "{{days}} days remaining", { days: trialStatus.daysRemaining });
 
   return (
-    <div style={{ display: 'flex', flexDirection: 'column', gap: '1rem' }}>
+    <div style={{ display: "flex", flexDirection: "column", gap: "1rem" }}>
       <p>
         {t(
-          'onboarding.freeTrial.body',
-          'You have full access to Stirling PDF Pro features during your trial. Enjoy unlimited conversions, larger file sizes, and priority processing.'
+          "onboarding.freeTrial.body",
+          "You have full access to Stirling PDF Pro features during your trial. Enjoy unlimited conversions, larger file sizes, and priority processing.",
         )}
       </p>
-      <div style={{
-        background: 'rgba(255, 255, 255, 0.1)',
-        borderRadius: '8px',
-        padding: '1rem',
-        textAlign: 'center'
-      }}>
-        <div style={{ fontSize: '1.25rem', fontWeight: 'bold', marginBottom: '0.5rem' }}>
-          {daysText}
-        </div>
-        <div style={{ fontSize: '0.9rem', opacity: 0.9 }}>
-          {t('onboarding.freeTrial.trialEnds', 'Trial ends {{date}}', { date: trialEndDate })}
+      <div
+        style={{
+          background: "rgba(255, 255, 255, 0.1)",
+          borderRadius: "8px",
+          padding: "1rem",
+          textAlign: "center",
+        }}
+      >
+        <div style={{ fontSize: "1.25rem", fontWeight: "bold", marginBottom: "0.5rem" }}>{daysText}</div>
+        <div style={{ fontSize: "0.9rem", opacity: 0.9 }}>
+          {t("onboarding.freeTrial.trialEnds", "Trial ends {{date}}", { date: trialEndDate })}
         </div>
       </div>
-      <p style={{ fontSize: '0.9rem', opacity: 0.9 }}>
-        {afterTrialMessage}
-      </p>
+      <p style={{ fontSize: "0.9rem", opacity: 0.9 }}>{afterTrialMessage}</p>
     </div>
   );
 };
 
 export default function FreeTrialSlide({ trialStatus }: FreeTrialSlideProps): SlideConfig {
   return {
-    key: 'free-trial',
+    key: "free-trial",
     title: <FreeTrialSlideTitle />,
     body: <FreeTrialSlideBody trialStatus={trialStatus} />,
     background: {
-      gradientStops: ['#10B981', '#06B6D4'],
+      gradientStops: ["#10B981", "#06B6D4"],
       circles: UNIFIED_CIRCLE_CONFIG,
     },
   };