feat(docker): Dockerfile, cloud server support, and parallel release pipeline (#174)

* added doceker build

* added docker files

* feat(ci): add Docker build phase to release pipeline and .dockerignore

Restructure release.yml into parallel build phases: build-desktop (matrix)
and build-docker run concurrently after create-release. Docker image is
pushed to GHCR and pull instructions are appended to release notes.
publish-release now gates on both phases succeeding.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* style: apply cargo fmt to jsonrpc host binding

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix(review): address PR review findings

- .env.example: comment out OPENHUMAN_CORE_HOST so Docker's 0.0.0.0
  default isn't overridden when users copy the example file
- cli.rs: add --host to print_general_help() usage line for consistency
- jsonrpc.rs: use tuple bind (host, port) for IPv6 support, add
  debug logging with source tracking (CLI/env/default) before bind
- release.yml: push only staging tag in build-docker, promote to
  versioned + latest in publish-release after all builds succeed;
  cleanup-failed-release deletes the staging image on failure

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.env.example

@@ -23,6 +23,9 @@ JWT_TOKEN=
 # ---------------------------------------------------------------------------
 # Core process
 # ---------------------------------------------------------------------------
+# [optional] Default: 127.0.0.1 (use 0.0.0.0 for Docker / cloud).
+# Leave unset to keep the default; the Docker image sets 0.0.0.0 automatically.
+# OPENHUMAN_CORE_HOST=
 # [optional] Default: 7788
 OPENHUMAN_CORE_PORT=7788
 # [optional] Default: http://127.0.0.1:7788/rpc