Ensure user comments are confirmed as saved on the Map screen

[Copilot]

Users had no way to verify their feedback comments were received after submission — the app gave no application-level signal of success or failure.

Changes

src/app/App.tsx

• Added SubmissionToast component: fixed-position, auto-dismissing (6 s) notification rendered on every feedback submission
  • Success: green "✓ Your feedback was saved." with a "View →" link to the created GitHub issue, so users can confirm their comment landed
  • Error: red "✕ Could not save feedback — please try again."
• Wired onSubmitSuccess / onSubmitError into FeedbackKitProvider — these fire for both session task comments and issue reports

<FeedbackKitProvider
  apiEndpoint="/api/feedback"
  onSubmitSuccess={handleSubmitSuccess}   // shows toast + link to GH issue
  onSubmitError={handleSubmitError}       // shows error toast
>

vite.config.ts

• Fixed broken build: the @thd-spatial-ai/feedback-kit alias was hard-coded to a local sibling source tree (../feedback-kit/src/index.ts) that doesn't exist in CI. Now checks for that path with fs.existsSync and falls back to the installed npm dist when absent.