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.

.github/workflows/release.yml

@@ -2,9 +2,11 @@ name: Release 3X-UI
 
 on:
   workflow_dispatch:
+  # Only main (dev channel) and version tags ship binaries; build any other
+  # branch on demand via workflow_dispatch.
   push:
     branches:
-      - "**"
+      - main
     tags:
       - "v*.*.*"
     paths:
@@ -17,17 +19,6 @@ on:
       - "x-ui.service.arch"
       - "x-ui.service.rhel"
       - ".github/workflows/release.yml"
-  pull_request:
-    paths:
-      - "**.go"
-      - "go.mod"
-      - "go.sum"
-      - "**.sh"
-      - "frontend/**"
-      - "x-ui.service.debian"
-      - "x-ui.service.arch"
-      - "x-ui.service.rhel"
-      - ".github/workflows/release.yml"
 
 jobs:
   build: