feat(podman): add optional Podman setup and documentation (#16273)

* feat(podman): add optional Podman setup and documentation

- Introduced `setup-podman.sh` for one-time host setup of OpenClaw in a rootless Podman environment, including user creation, image building, and launch script installation.
- Added `run-openclaw-podman.sh` for running the OpenClaw gateway as a Podman container.
- Created `openclaw.podman.env` for environment variable configuration.
- Updated documentation to include Podman installation instructions and a new dedicated Podman guide.
- Added a systemd Quadlet unit for managing the OpenClaw service as a user service.

* fix: harden Podman setup and docs (#16273) (thanks @DarwinsBuddy)

* style: format cli credentials

---------

Co-authored-by: Peter Steinberger <steipete@gmail.com>

CHANGELOG.md

@@ -44,6 +44,7 @@ Docs: https://docs.openclaw.ai
 
 ### Changes
 
+- Install: add optional Podman-based setup: `setup-podman.sh` for one-time host setup (openclaw user, image, launch script, systemd quadlet), `run-openclaw-podman.sh launch` / `launch setup`; systemd Quadlet unit for openclaw user service; docs for rootless container, openclaw user (subuid/subgid), and quadlet (troubleshooting). (#16273) Thanks @DarwinsBuddy.
 - Discord: send voice messages with waveform previews from local audio files (including silent delivery). (#7253) Thanks @nyanjou.
 - Discord: add configurable presence status/activity/type/url (custom status defaults to activity text). (#10855) Thanks @h0tp-ftw.
 - Slack/Plugins: add thread-ownership outbound gating via `message_sending` hooks, including @-mention bypass tracking and Slack outbound hook wiring for cancel/modify behavior. (#15775) Thanks @DarlingtonDeveloper.