Add push history state support to LiveComponent

[ajgarlag]

Q	A
Bug fix?	no
New feature?	yes
Deprecations?	no
Documentation?	yes
Issues	Fix #3149
License	MIT

This PR adds support for pushing browser history entries when a LiveComponent updates URL-bound LiveProp values.

Until now, URL updates were always done with history.replaceState(), which overwrote the current entry. With this change, components can opt in to history.pushState() so users can navigate previous component states via the browser back button (for example, previous pages in pagination or prior filter states in search UIs).

Included changes:

• Added a new pushHistoryState parameter to #[AsLiveComponent(...)] (default: false).
• Exposed this option in component metadata as push_history_state.
• Added LiveComponentMetadata::hasPushHistoryStateEnabled() to read the flag.
• Updated LiveUrlSubscriber to include a new response header:
  • X-Live-Url-Push-History-State: 1|0
• Updated frontend BackendResponse to parse the new header.
• Updated frontend URL update logic to choose:
  • history.pushState(...) when enabled
  • history.replaceState(...) otherwise (current behavior preserved)

[github-actions]

📊 Packages dist files size difference

Thanks for the PR! Here is the difference in size of the packages dist files between the base branch and the PR.
Please review the changes and make sure they are expected.

File	Before (Size / Gzip)	After (Size / Gzip)
LiveComponent
live_controller.d.ts	7.54 kB / 1.96 kB	7.61 kB+1% 📈 / 1.98 kB+1% 📈
live_controller.js	82.56 kB / 18.35 kB	82.83 kB0% / 18.43 kB0%