Fix seeder: origin mismatch + robust Dockerfile

Two root causes for seeding not working on production:

1. Origin mismatch: The seeder writes content IDs as
   http://localhost:7777/content/... but the app was using
   window.location.origin (the user's actual browser URL) to
   query the relay. Introduced VITE_CONTENT_ORIGIN env var
   baked into the Docker build so both sides use the same origin.

2. Dockerfile.seed fragility: Replaced --omit=dev + global tsx
   with a cleaner approach that strips sharp from package.json
   (the only native dep that fails on Alpine) then does a full
   npm install, ensuring tsx/esbuild and all applesauce deps
   resolve correctly.

Also improved wait-for-relay to accept any HTTP response (some
relays return 4xx for plain GET) and increased max attempts.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/composables/useContentDiscovery.ts

@@ -170,11 +170,10 @@ export function useContentDiscovery() {
       if (!effectiveAlgo) return contents
 
       const statsMap = contentStatsMap.value
-      const origin = window.location.origin
 
       // Build entries array: [Content, stats] for each content item
       const withStats: [Content, ContentStats][] = contents.map((c) => {
-        const externalId = `${origin}/content/${c.id}`
+        const externalId = getExternalContentId(c.id)
         return [c, statsMap.get(externalId) || EMPTY_STATS]
       })
 

src/composables/useNostr.ts

@@ -8,12 +8,20 @@ import { eventStore, pool, appRelays, factory, APP_RELAYS } from '../lib/nostr'
 import { accountManager } from '../lib/accounts'
 import { useObservable } from './useObservable'
 
+/**
+ * The origin used for Nostr content identifiers.
+ * In Docker/production the env var is baked in at build time so it matches
+ * the origin the seeder uses, regardless of how users access the app.
+ */
+const CONTENT_ORIGIN: string =
+  import.meta.env.VITE_CONTENT_ORIGIN || window.location.origin
+
 /**
  * Build the external content identifier used in Nostr tags.
  * Matches indeehub convention: {origin}/content/{contentId}
  */
 export function getExternalContentId(contentId: string): string {
-  return `${window.location.origin}/content/${contentId}`
+  return `${CONTENT_ORIGIN}/content/${contentId}`
 }
 
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