feat(attachments): R2 toggle, storage metrics, and demo R2 config

Add an ATTACHMENTS_ENABLED switch (default on when R2 is bound) via a
central getAttachmentBucket helper, surface R2 + estimated KV usage
against the free tier on the status page and /api/stats (refreshed by the
hourly cron), let setup.sh create and wire the R2 bucket, and bind the
demo bucket so the deployed demo has attachments.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/routes/admin/emails.tsx

@@ -10,6 +10,7 @@ import { logger } from "../../lib/logger";
 import { Layout, clampText } from "./ui";
 import { deleteKeysWithConcurrency } from "./helpers";
 import { feedRssUrl, feedAtomUrl, feedEmailAddress } from "../../utils/urls";
+import { getAttachmentBucket } from "../../utils/attachments";
 import { emailsPageScript } from "../../scripts/generated/emails-page";
 
 type AppEnv = { Bindings: Env };
@@ -643,9 +644,10 @@ emailsRouter.post("/emails/:emailKey/delete", async (c) => {
       await emailStorage.put(feedMetadataKey, JSON.stringify(feedMetadata));
     }
 
-    if (env.ATTACHMENT_BUCKET && attachmentIds.length > 0) {
+    const attachmentBucket = getAttachmentBucket(env);
+    if (attachmentBucket && attachmentIds.length > 0) {
       await Promise.allSettled(
-        attachmentIds.map((id) => env.ATTACHMENT_BUCKET!.delete(id)),
+        attachmentIds.map((id) => attachmentBucket.delete(id)),
       );
     }
 
@@ -726,9 +728,10 @@ emailsRouter.post("/feeds/:feedId/emails/bulk-delete", async (c) => {
       );
       await emailStorage.put(feedMetadataKey, JSON.stringify(feedMetadata));
 
-      if (env.ATTACHMENT_BUCKET && r2AttachmentIds.length > 0) {
+      const attachmentBucket = getAttachmentBucket(env);
+      if (attachmentBucket && r2AttachmentIds.length > 0) {
         await Promise.allSettled(
-          r2AttachmentIds.map((id) => env.ATTACHMENT_BUCKET!.delete(id)),
+          r2AttachmentIds.map((id) => attachmentBucket.delete(id)),
         );
       }
 

src/routes/admin/feeds.tsx

@@ -7,6 +7,7 @@ import { waitUntilSafe } from "../../utils/worker";
 import { feedRssUrl, feedEmailAddress } from "../../utils/urls";
 import { logger } from "../../lib/logger";
 import { sendUnsubscribes } from "../../utils/unsubscribe";
+import { getAttachmentBucket } from "../../utils/attachments";
 import { Layout } from "./ui";
 import {
   addFeedToList,
@@ -555,7 +556,7 @@ feedsRouter.post("/:feedId/delete", async (c) => {
     waitUntilSafe(
       c,
       purgeFeedKeysStep(emailStorage, feedId, {
-        bucket: env.ATTACHMENT_BUCKET,
+        bucket: getAttachmentBucket(env),
       }),
     );
 
@@ -594,7 +595,7 @@ feedsRouter.post("/:feedId/purge", async (c) => {
     const step = await purgeFeedKeysStep(emailStorage, feedId, {
       cursor,
       limit,
-      bucket: env.ATTACHMENT_BUCKET,
+      bucket: getAttachmentBucket(env),
     });
 
     return c.json({