fix: require VITE_CONVEX_URL env var for edge functions and clarify publishing workflow

- Add VITE_CONVEX_URL requirement to Netlify env vars for edge function runtime
- Improve error messages in edge functions when Convex URL is missing
- Add "How publishing works" explanation to README, setup guide, and docs
- Update deployment instructions across all documentation

netlify/edge-functions/api.ts

@@ -10,11 +10,11 @@ export default async function handler(
 
   if (!convexUrl) {
     return new Response(
-      JSON.stringify({ error: "Configuration error: Missing Convex URL" }),
-      {
-        status: 500,
-        headers: { "Content-Type": "application/json" },
-      },
+      JSON.stringify({
+        error:
+          "VITE_CONVEX_URL not set. Add it to Netlify environment variables.",
+      }),
+      { status: 500, headers: { "Content-Type": "application/json" } },
     );
   }
 

netlify/edge-functions/rss.ts

@@ -9,9 +9,10 @@ export default async function handler(
     Deno.env.get("VITE_CONVEX_URL") || Deno.env.get("CONVEX_URL");
 
   if (!convexUrl) {
-    return new Response("Configuration error: Missing Convex URL", {
-      status: 500,
-    });
+    return new Response(
+      "Configuration error: VITE_CONVEX_URL not set. Add it to Netlify environment variables.",
+      { status: 500, headers: { "Content-Type": "text/plain" } },
+    );
   }
 
   // Construct the Convex site URL for the HTTP endpoint

netlify/edge-functions/sitemap.ts

@@ -9,9 +9,10 @@ export default async function handler(
     Deno.env.get("VITE_CONVEX_URL") || Deno.env.get("CONVEX_URL");
 
   if (!convexUrl) {
-    return new Response("Configuration error: Missing Convex URL", {
-      status: 500,
-    });
+    return new Response(
+      "Configuration error: VITE_CONVEX_URL not set. Add it to Netlify environment variables.",
+      { status: 500, headers: { "Content-Type": "text/plain" } },
+    );
   }
 
   // Construct the Convex site URL for the HTTP endpoint