ci: add workflow_dispatch trigger to all workflows

Lets any workflow be manually re-run against a branch via
\`gh workflow run <file>\` or the Actions UI "Run workflow" button,
without needing a new commit — useful when a commit was skipped or when
debugging a flaky job.

No behavior change for the existing push / pull_request triggers.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: dogmar

.github/workflows/ci.yml

@@ -3,6 +3,7 @@ name: CI
 on:
   pull_request:
     branches: [main]
+  workflow_dispatch:
 
 permissions:
   contents: read

.github/workflows/deploy-site.yml

@@ -3,6 +3,7 @@ name: Deploy demo site
 on:
   push:
     branches: [main]
+  workflow_dispatch:
 
 permissions:
   contents: read

.github/workflows/pr-title.yml

@@ -3,6 +3,7 @@ name: PR title check
 on:
   pull_request:
     types: [opened, edited, synchronize, reopened]
+  workflow_dispatch:
 
 jobs:
   check:

.github/workflows/release.yml

@@ -4,6 +4,7 @@ on:
   push:
     branches:
       - main
+  workflow_dispatch:
 
 permissions:
   id-token: write

.github/workflows/sync-readme.yml

@@ -10,6 +10,7 @@ on:
       - scripts/sync-readme.sh
       - vite.config.ts
       - README.md
+  workflow_dispatch:
 
 permissions:
   contents: write