feat: initial project prototype (#1)

### Explanation

_No response_

### Issue

_No response_

### Attestations

- [x] I have read and agree to the [Code of Conduct](https://docs.nhcarrigan.com/community/coc/)
- [x] I have read and agree to the [Community Guidelines](https://docs.nhcarrigan.com/community/guide/).
- [x] My contribution complies with the [Contributor Covenant](https://docs.nhcarrigan.com/dev/covenant/).

### Dependencies

- [x] I have pinned the dependencies to a specific patch version.

### Style

- [x] I have run the linter and resolved any errors.
- [x] My pull request uses an appropriate title, matching the conventional commit standards.
- [x] My scope of feat/fix/chore/etc. correctly matches the nature of changes in my pull request.

### Tests

- [ ] My contribution adds new code, and I have added tests to cover it.
- [ ] My contribution modifies existing code, and I have updated the tests to reflect these changes.
- [ ] All new and existing tests pass locally with my changes.
- [ ] Code coverage remains at or above the configured threshold.

### Documentation

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### Versioning

Major - My pull request introduces a breaking change.

Reviewed-on: #1
Co-authored-by: Naomi Carrigan <commits@nhcarrigan.com>
Co-committed-by: Naomi Carrigan <commits@nhcarrigan.com>

src/modules/translate.ts

@@ -0,0 +1,94 @@
+/**
+ * @copyright nhcarrigan
+ * @license Naomi's Public License
+ * @author Naomi Carrigan
+ */
+
+import {
+  MessageFlags,
+  type MessageContextMenuCommandInteraction,
+} from "discord.js";
+import { supportedLocales } from "../config/locales.js";
+import { i18n } from "../utils/i18n.js";
+import { getLocale } from "./getLocale.js";
+
+/**
+ * Translates a message to the user's locale.
+ * @param interaction -- The interaction payload from Discord.
+ */
+// eslint-disable-next-line max-statements, max-lines-per-function -- This is a complex function.
+export const translate = async(
+  interaction: MessageContextMenuCommandInteraction,
+): Promise<void> => {
+  await interaction.deferReply({ flags: [ MessageFlags.Ephemeral ] });
+  const targetLocale = getLocale(interaction);
+
+  const isEntitled = interaction.entitlements.find((entitlement) => {
+    return entitlement.userId === interaction.user.id && entitlement.isActive();
+  });
+
+  if (!isEntitled) {
+    await interaction.editReply({
+      content: i18n("subscription-required", targetLocale),
+    });
+    return;
+  }
+
+  if (!supportedLocales.includes(targetLocale)) {
+    await interaction.editReply(i18n("unsupported-locale", targetLocale, {
+      target: targetLocale,
+    }));
+    return;
+  }
+
+  const message = interaction.options.getMessage("message", true);
+  if (message.content === "") {
+    await interaction.editReply({
+      content: i18n("no-message-content", targetLocale),
+    });
+    return;
+  }
+  const sourceLocaleRequestParameters = new URLSearchParams();
+  sourceLocaleRequestParameters.append("q", message.content);
+  sourceLocaleRequestParameters.append(
+    "api_key",
+    process.env.TRANSLATE_TOKEN ?? "",
+  );
+  const sourceLocaleRequest = await fetch(
+    "https://trans.nhcarrigan.com/detect",
+    {
+      body:   sourceLocaleRequestParameters,
+      method: "POST",
+    },
+  );
+  // eslint-disable-next-line @typescript-eslint/consistent-type-assertions -- .json() doesn't accept a generic.
+  const [ sourceLocale ] = (await sourceLocaleRequest.json()) as Array<{
+    confidence: number;
+    language:   string;
+  }>;
+  const translationRequestParameters = new URLSearchParams();
+  translationRequestParameters.append("q", message.content);
+  translationRequestParameters.append("source", sourceLocale?.language ?? "en");
+  translationRequestParameters.append("target", targetLocale);
+  translationRequestParameters.append(
+    "api_key",
+    process.env.TRANSLATE_TOKEN ?? "",
+  );
+  const translationRequest = await fetch(
+    "https://trans.nhcarrigan.com/translate",
+    { body: translationRequestParameters, method: "POST" },
+  );
+  // eslint-disable-next-line @typescript-eslint/consistent-type-assertions -- .json() doesn't accept a generic.
+  const translation = (await translationRequest.json()) as {
+    translatedText: string;
+  };
+
+  await interaction.editReply({
+    content: i18n("translation", targetLocale, {
+      confidence:  sourceLocale?.confidence,
+      language:    sourceLocale?.language,
+      lng:         targetLocale,
+      translation: translation.translatedText,
+    }),
+  });
+};