feat(launcher): add --version / -v flag to print app version

- Exits early with `SubMiner <version>` output, no app binary required
- Maps `-v` at root level without conflicting with `stats cleanup -v`
- Adds `version: boolean` to `Args` type and default args
- Documents flag in docs-site and adds changelog fragment

launcher/config/cli-parser-builder.ts

@@ -57,6 +57,7 @@ function applyRootOptions(program: Command): void {
     .option('-p, --profile <profile>', 'MPV profile')
     .option('--start', 'Explicitly start overlay')
     .option('--log-level <level>', 'Log level')
+    .option('-v, --version', 'Show SubMiner version')
     .option('-u, --update', 'Check for updates')
     .option('-R, --rofi', 'Use rofi picker')
     .option('-S, --start-overlay', 'Auto-start overlay')