chore: add v0.4.8 changelog and improve scroll behavior (#234)

* chore: add v0.4.8 changelog and improve scroll behavior

- Add v0.4.8 changelog entries for recent fixes
- Fix forced scroll to bottom when returning from other tabs
- Smooth session switch with loading transition overlay
- Auto-scroll to bottom after mermaid diagram rendering
- Bump version to 0.4.8

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

* fix: replace blob URLs with persistent download URLs and add image preview

- Replace blob URLs with /api/hermes/download URLs after upload so
  attachments survive page refresh
- Add click-to-preview overlay for image attachments
- Move upload directory from /tmp to ~/.hermes-web-ui/upload

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

* fix: replace findLast with reverse+find for ES2022 compat

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

* chore: bump TypeScript lib target from ES2022 to ES2023

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

* docs: add changelog entries for blob URL fix, image preview and upload dir

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

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "hermes-web-ui",
-  "version": "0.4.7",
+  "version": "0.4.8",
   "description": "Self-hosted AI chat dashboard for Hermes Agent — multi-model (Claude, GPT, Gemini, DeepSeek) web UI with Telegram, Discord, Slack, WhatsApp integration",
   "repository": {
     "type": "git",