chore(ci): stop release and CodeQL runs on PRs, drop deploy smoke tests

The release matrix (7 Linux cross-builds + a CGO Windows build) ran on every
PR and on every branch push, so a PR from a repo branch built everything
twice. Release binaries now build only on main (dev channel) and version
tags; any other branch can still be built via workflow_dispatch.

CodeQL keeps its push-to-main and weekly scans but no longer runs per PR.

The deploy smoke workflow fired on every Release completion only to skip
its jobs; deploy/test/smoke-noninteractive.sh stays for manual runs.

docs/architecture.md

@@ -292,7 +292,7 @@ node heartbeat every 5s, periodic traffic resets (hourly/daily/weekly/monthly).
 ├── install.sh / update.sh / x-ui.sh                        # VPS install + management CLI
 ├── x-ui.service.*  / x-ui.rc                               # systemd units (debian/rhel/arch) + rc script
 ├── windows_files/                                          # Windows service support
-└── .github/workflows/        # CI: ci.yml, codeql.yml, docker.yml, release.yml, smoke.yml,
+└── .github/workflows/        # CI: ci.yml, codeql.yml, docker.yml, release.yml,
                               #     mutation.yml, cleanup_caches.yml, claude-pr-review.yml,
                               #     claude-issue-analyst.yml
 ```
@@ -583,7 +583,7 @@ root → `go build ./...` / `go run main.go`.
 **Docker:** `docker compose up -d` (uses `Dockerfile` + `DockerEntrypoint.sh`).
 
 **CI** (`.github/workflows/`): `ci.yml` (build/test/lint), `codeql.yml` (security scan),
-`smoke.yml` (smoke tests), `mutation.yml` (mutation testing), `docker.yml` + `release.yml`
+`mutation.yml` (mutation testing), `docker.yml` + `release.yml`
 (multi-arch image + release builds), `cleanup_caches.yml`, `claude-pr-review.yml` (PR review
 only - it changes no code), `claude-issue-analyst.yml` (issue triage).