feat: add named kind constants, streaming updates, and fix reads/links tabs

- Create src/config/kinds.ts with named Nostr kind constants
- Add streaming support to fetchAllReads and fetchLinks with onItem callbacks
- Update all services to use KINDS constants instead of magic numbers
- Add mergeReadItem utility for DRY state management
- Add fallbackTitleFromUrl for external links without titles
- Relax validation to allow external items without titles
- Update Me.tsx to use streaming with Map-based state for reads/links
- Fix refresh to merge new data instead of clearing state
- Fix empty states for Reads and Links tabs (no more infinite skeletons)
- Services updated: readsService, linksService, libraryService, bookmarkService, exploreService, highlights/fetchByAuthor

src/utils/readItemMerge.ts

@@ -0,0 +1,74 @@
+import { ReadItem } from '../services/readsService'
+
+/**
+ * Merges a ReadItem into a state map, returning whether the state changed.
+ * Uses most recent reading activity to determine precedence.
+ */
+export function mergeReadItem(
+  stateMap: Map<string, ReadItem>,
+  incoming: ReadItem
+): boolean {
+  const existing = stateMap.get(incoming.id)
+  
+  if (!existing) {
+    stateMap.set(incoming.id, incoming)
+    return true
+  }
+  
+  // Merge by taking the most recent reading activity
+  const existingTime = existing.readingTimestamp || existing.markedAt || 0
+  const incomingTime = incoming.readingTimestamp || incoming.markedAt || 0
+  
+  if (incomingTime > existingTime) {
+    // Keep existing data, but update with newer reading metadata
+    stateMap.set(incoming.id, {
+      ...existing,
+      ...incoming,
+      // Preserve event data if incoming doesn't have it
+      event: incoming.event || existing.event,
+      title: incoming.title || existing.title,
+      summary: incoming.summary || existing.summary,
+      image: incoming.image || existing.image,
+      published: incoming.published || existing.published,
+      author: incoming.author || existing.author
+    })
+    return true
+  }
+  
+  // If timestamps are equal but incoming has additional data, merge it
+  if (incomingTime === existingTime && (!existing.event && incoming.event || !existing.title && incoming.title)) {
+    stateMap.set(incoming.id, {
+      ...existing,
+      ...incoming,
+      event: incoming.event || existing.event,
+      title: incoming.title || existing.title,
+      summary: incoming.summary || existing.summary,
+      image: incoming.image || existing.image,
+      published: incoming.published || existing.published,
+      author: incoming.author || existing.author
+    })
+    return true
+  }
+  
+  return false
+}
+
+/**
+ * Extracts a readable title from a URL when no title is available.
+ * Removes protocol, www, and shows domain + path.
+ */
+export function fallbackTitleFromUrl(url: string): string {
+  try {
+    const parsed = new URL(url)
+    let title = parsed.hostname.replace(/^www\./, '')
+    if (parsed.pathname && parsed.pathname !== '/') {
+      const path = parsed.pathname.slice(0, 40)
+      title += path.length < parsed.pathname.length ? path + '...' : path
+    }
+    return title
+  } catch {
+    // If URL parsing fails, just return the URL truncated
+    return url.length > 50 ? url.slice(0, 47) + '...' : url
+  }
+}
+