fix: dashboard menu clickability + expiration date UX (#753)

* fix: dashboard menu clickability + expiration date UX

Dashboard actions menu:
- Inactive (expired/removed) rows dimmed via their cells instead of the
  row, so `opacity` no longer creates a stacking context that trapped the
  actions dropdown beneath later rows and made its items unclickable.
- Add an "Extend 6 months" menu item for expired repos/PRs/gists.

Expiration form (anonymize):
- Fix the "After , the content will be removed." blank date: guard the
  helper text and add min/max validation feedback so an invalid pick no
  longer nulls the model into a broken sentence.
- Add a `min` (today) so past dates can no longer be selected, and
  compute min/max from local date parts (not UTC) to avoid a timezone
  off-by-one in the native picker.
- Default expiration is now 6 months (single source of truth, removing a
  latent double-offset bug); max stays at 1 year.
- Block submitting a missing/out-of-range expiration date.

Backend:
- New POST /:id/extend endpoint for repos, PRs and gists that pushes the
  expiration +6 months and re-anonymizes so expired items come back
  online, mirroring the refresh flow. Shared extendExpirationDate helper.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* fix: add frontend translation for invalid_status error code

The new /extend endpoints throw an "invalid_status" AnonymousError, which
the error-code coverage test requires to have a locale entry.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

src/server/routes/pullRequest-private.ts

@@ -6,6 +6,7 @@ import {
   getUser,
   handleError,
   isOwnerOrAdmin,
+  extendExpirationDate,
 } from "./route-utils";
 import AnonymousError from "../../core/AnonymousError";
 import { IAnonymizedPullRequestDocument } from "../../core/model/anonymizedPullRequests/anonymizedPullRequests.types";
@@ -36,6 +37,47 @@ router.post(
   }
 );
 
+// extend the expiration of a pullRequest (default +6 months) and bring it back
+// online if it had expired
+router.post(
+  "/:pullRequestId/extend",
+  async (req: express.Request, res: express.Response) => {
+    try {
+      const pullRequest = await getPullRequest(req, res, { nocheck: true });
+      if (!pullRequest) return;
+
+      if (
+        pullRequest.status == RepositoryStatus.PREPARING ||
+        pullRequest.status == RepositoryStatus.REMOVING ||
+        pullRequest.status == RepositoryStatus.EXPIRING ||
+        pullRequest.status == RepositoryStatus.REMOVED
+      ) {
+        throw new AnonymousError("invalid_status", {
+          object: pullRequest,
+          httpStatus: 409,
+        });
+      }
+
+      const user = await getUser(req);
+      isOwnerOrAdmin([pullRequest.owner.id], user);
+
+      const newExpiration = extendExpirationDate(
+        pullRequest.model.options.expirationDate
+      );
+      pullRequest.model.options.expirationDate = newExpiration;
+      await AnonymizedPullRequestModel.updateOne(
+        { _id: pullRequest.model._id },
+        { $set: { "options.expirationDate": newExpiration } }
+      ).exec();
+
+      await pullRequest.updateIfNeeded({ force: true });
+      res.json({ status: pullRequest.status, expirationDate: newExpiration });
+    } catch (error) {
+      handleError(error, res, req);
+    }
+  }
+);
+
 // delete a pullRequest
 router.delete(
   "/:pullRequestId/",