flash: bump manifest to 2.8.0

Serve v2.8.0 (manual homing, StallGuard opt-in, friendly Motion Tuning) from
the flasher. Also redeploys Pages via the flash/** path trigger, since the
release-published deploy has failed the github-pages env gate every release.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: daniel-frenkel

flash/manifest.json

@@ -1,6 +1,6 @@
 {
   "name": "Ropener",
-  "version": "2.7.1",
+  "version": "2.8.0",
   "home_assistant_domain": "esphome",
   "new_install_prompt_erase": false,
   "builds": [