feat(unsubscribe): RFC 8058 one-click unsubscribe on feed deletion

Capture each sender's List-Unsubscribe one-click URL during ingestion
(stored per sender in feed metadata, mirroring the iconDomain pattern) and
fire one-click POSTs via ctx.waitUntil when a feed is deleted, so newsletters
stop mailing the now-dead address. Tracked with a new unsubscribes_sent
counter surfaced on the status page and /api/stats.

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

src/routes/admin/feeds.tsx

@@ -6,6 +6,7 @@ import { bumpCounters } from "../../utils/stats";
 import { waitUntilSafe } from "../../utils/worker";
 import { feedRssUrl, feedEmailAddress } from "../../utils/urls";
 import { logger } from "../../lib/logger";
+import { sendUnsubscribes } from "../../utils/unsubscribe";
 import { Layout } from "./ui";
 import {
   addFeedToList,
@@ -13,6 +14,7 @@ import {
   removeFeedFromList,
   removeFeedsFromListBulk,
   purgeFeedKeysStep,
+  collectUnsubscribeUrls,
 } from "./helpers";
 
 type AppEnv = { Bindings: Env };
@@ -537,12 +539,19 @@ feedsRouter.post("/:feedId/delete", async (c) => {
   const wantsJson = (c.req.header("Accept") || "").includes("application/json");
 
   try {
+    // Read unsubscribe URLs before the metadata is deleted below.
+    const unsubscribeUrls = await collectUnsubscribeUrls(emailStorage, feedId);
+
     await deleteFeedFast(emailStorage, feedId);
     const removed = await removeFeedFromList(emailStorage, feedId);
     if (removed) {
       await bumpCounters(emailStorage, { feeds_deleted: 1 });
     }
 
+    if (unsubscribeUrls.length > 0) {
+      waitUntilSafe(c, sendUnsubscribes(unsubscribeUrls, env));
+    }
+
     waitUntilSafe(
       c,
       purgeFeedKeysStep(emailStorage, feedId, {
@@ -638,9 +647,12 @@ feedsRouter.post("/bulk-delete", async (c) => {
       const okIds: string[] = [];
       const failures: Array<{ feedId: string; error: string }> = [];
       const warnings: Array<{ feedId: string; warning: string }> = [];
+      const unsubscribeUrls: string[] = [];
 
       for (const feedId of parsedFeedIds) {
         try {
+          // Read unsubscribe URLs before the feed metadata is deleted.
+          const urls = await collectUnsubscribeUrls(emailStorage, feedId);
           const result = await deleteFeedFastDetailed(emailStorage, feedId);
           if (!result.ok) {
             failures.push({
@@ -660,6 +672,7 @@ feedsRouter.post("/bulk-delete", async (c) => {
             });
           }
 
+          unsubscribeUrls.push(...urls);
           okIds.push(feedId);
         } catch (error) {
           logger.error("Error bulk deleting feed", {
@@ -677,6 +690,10 @@ feedsRouter.post("/bulk-delete", async (c) => {
         });
       }
 
+      if (unsubscribeUrls.length > 0) {
+        waitUntilSafe(c, sendUnsubscribes(unsubscribeUrls, env));
+      }
+
       const removed = new Set(deletedFeedIds);
       okIds.forEach((feedId) => {
         if (!removed.has(feedId)) {
@@ -711,11 +728,17 @@ feedsRouter.post("/bulk-delete", async (c) => {
     }
 
     const okIds: string[] = [];
+    const unsubscribeUrls: string[] = [];
 
     for (const feedId of parsedFeedIds) {
       try {
+        // Read unsubscribe URLs before the feed metadata is deleted.
+        const urls = await collectUnsubscribeUrls(emailStorage, feedId);
         const result = await deleteFeedFastDetailed(emailStorage, feedId);
-        if (result.ok) okIds.push(feedId);
+        if (result.ok) {
+          unsubscribeUrls.push(...urls);
+          okIds.push(feedId);
+        }
       } catch (error) {
         logger.error("Error bulk deleting feed", {
           feedId,
@@ -731,6 +754,10 @@ feedsRouter.post("/bulk-delete", async (c) => {
       });
     }
 
+    if (unsubscribeUrls.length > 0) {
+      waitUntilSafe(c, sendUnsubscribes(unsubscribeUrls, env));
+    }
+
     return c.redirect(
       `${redirectBase}&message=bulkDeleted&count=${deletedFeedIds.length}`,
     );

src/routes/admin/helpers.ts

@@ -1,4 +1,4 @@
-import { EmailData, FeedList, FeedListItem } from "../../types";
+import { EmailData, FeedList, FeedListItem, FeedMetadata } from "../../types";
 import { FEEDS_LIST_KEY } from "../../config/constants";
 import { logger } from "../../lib/logger";
 
@@ -132,6 +132,28 @@ export async function removeFeedFromList(
   return removed.includes(feedId);
 }
 
+/**
+ * Read a feed's stored RFC 8058 one-click unsubscribe URLs (one per sender).
+ * Must be called before the feed metadata is deleted. Never throws.
+ */
+export async function collectUnsubscribeUrls(
+  emailStorage: KVNamespace,
+  feedId: string,
+): Promise<string[]> {
+  try {
+    const metadata = (await emailStorage.get(`feed:${feedId}:metadata`, {
+      type: "json",
+    })) as FeedMetadata | null;
+    return Object.values(metadata?.unsubscribe ?? {});
+  } catch (error) {
+    logger.error("Error reading unsubscribe URLs", {
+      feedId,
+      error: String(error),
+    });
+    return [];
+  }
+}
+
 export async function purgeFeedKeysStep(
   emailStorage: KVNamespace,
   feedId: string,