feat: complete Phase 2 tech debt remediation

- Extract shared RSS/Atom fetch logic into feed-fetcher utility (P1-3)
- Split email-processor into validateEmail/storeEmail functions (P1-6)
- Add stateless HMAC-SHA256 CSRF protection to admin forms (P2-8)
- Fix Hono<{ Bindings: Env }> type safety across all routes (P3-13)
- Add entries.test.ts and files.test.ts with full coverage (P1-7)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/routes/rss.ts

@@ -1,80 +1,37 @@
 import { Context } from "hono";
-import { Env, FeedConfig, FeedMetadata, EmailData } from "../types";
+import { Env } from "../types";
 import { generateRssFeed } from "../utils/feed-generator";
+import { fetchFeedData } from "../utils/feed-fetcher";
 
-/**
- * Generates an RSS feed for a specific feed ID
- */
-export async function handle(c: Context): Promise<Response> {
+export async function handle(c: Context<{ Bindings: Env }>): Promise<Response> {
   try {
-    // Type assertion for environment variables
-    const env = c.env as unknown as Env;
-
-    // Extract the feed ID from the route params
     const feedId = c.req.param("feedId");
-
     if (!feedId) {
       return new Response("Feed ID is required", { status: 400 });
     }
 
-    // Get the KV namespace
-    const emailStorage = env.EMAIL_STORAGE;
-
-    // Check if the feed exists
-    const feedMetadataKey = `feed:${feedId}:metadata`;
-    const feedMetadata = (await emailStorage.get(
-      feedMetadataKey,
-      "json",
-    )) as FeedMetadata | null;
-
-    if (!feedMetadata) {
+    const feedData = await fetchFeedData(feedId, c.env, "rss");
+    if (!feedData) {
       return new Response("Feed not found", { status: 404 });
     }
 
-    // Get feed configuration (title, description, etc.)
-    const feedConfigKey = `feed:${feedId}:config`;
-    const feedConfig = ((await emailStorage.get(
-      feedConfigKey,
-      "json",
-    )) as FeedConfig | null) || {
-      title: `Newsletter Feed ${feedId}`,
-      description: "Converted email newsletter",
-      site_url: `https://${env.DOMAIN}/rss/${feedId}`,
-      feed_url: `https://${env.DOMAIN}/rss/${feedId}`,
-      language: "en",
-      created_at: Date.now(),
-    };
-
-    // Get the emails for this feed (up to the last 20)
-    const emails = feedMetadata.emails.slice(0, 20);
-    const emailsData: EmailData[] = [];
-
-    // Fetch all email content
-    for (const email of emails) {
-      const emailData = (await emailStorage.get(
-        email.key,
-        "json",
-      )) as EmailData | null;
-      if (emailData) {
-        emailsData.push(emailData);
-      }
-    }
-
-    // Generate the RSS feed XML
-    const baseUrl = `https://${env.DOMAIN}`;
-    const rssXml = generateRssFeed(feedConfig, emailsData, baseUrl, feedId);
-
-    // Return the RSS feed with appropriate content type
+    const baseUrl = `https://${c.env.DOMAIN}`;
+    const rssXml = generateRssFeed(
+      feedData.feedConfig,
+      feedData.emails,
+      baseUrl,
+      feedId,
+    );
     const linkHeader = [
-      `<https://${env.DOMAIN}/hub>; rel="hub"`,
-      `<https://${env.DOMAIN}/rss/${feedId}>; rel="self"`,
+      `<${baseUrl}/hub>; rel="hub"`,
+      `<${baseUrl}/rss/${feedId}>; rel="self"`,
     ].join(", ");
 
     return new Response(rssXml, {
       status: 200,
       headers: {
         "Content-Type": "application/rss+xml",
-        "Cache-Control": "max-age=1800", // 30 minutes cache
+        "Cache-Control": "max-age=1800",
         Link: linkHeader,
       },
     });