chore: initial homelab stack config and sync tooling

Mirror the three production files (docker-compose.yml, .env, Caddyfile) that live on valhalla, plus the push/pull PowerShell scripts, CLAUDE.md, .gitignore/.gitattributes, and .claude/skills for ssh/apply/sync.

sync-prod.ps1

@@ -0,0 +1,25 @@
+# Pull the live production configs from valhalla into this repo, so local
+# matches what's actually deployed. Run at the start of any session where
+# you'll edit deployment config.
+#
+# Production is the source of truth. This OVERWRITES the local copies of
+# docker-compose.yml, .env, and Caddyfile -- commit or stash first.
+#
+# Usage: powershell -File sync-prod.ps1
+
+$ErrorActionPreference = "Stop"
+$PSNativeCommandUseErrorActionPreference = $true
+
+$server  = "ginnoir@valhalla"
+$repoDir = $PSScriptRoot
+
+Write-Host "Syncing production configs from $server ..."
+
+scp "${server}:~/htpc-download-box/docker-compose.yml" "$repoDir\docker-compose.yml"
+scp "${server}:~/htpc-download-box/.env"               "$repoDir\.env"
+scp "${server}:/config/caddy/Caddyfile"                "$repoDir\Caddyfile"
+
+Write-Host "Done. Files synced:"
+Get-ChildItem $repoDir -File |
+    Where-Object { $_.Name -in 'docker-compose.yml', '.env', 'Caddyfile' } |
+    Select-Object Name, Length, LastWriteTime