Migrate from npm to pnpm across entire project

• Update all GitHub workflow files to use pnpm instead of npm
• Replace npm commands with pnpm equivalents in devcontainer scripts
• Remove package-lock.json files and update to use pnpm-lock.yaml
• Consolidate node version references to use server/.nvmrc

.devcontainer/server/container-start-backend.sh

@@ -3,15 +3,20 @@
 # shellcheck disable=SC1091
 source /immich-devcontainer/container-common.sh
 
+log "Preparing Immich Nest API Server"
+log ""
+export CI=1
+run_cmd pnpm --filter immich install
+
 log "Starting Nest API Server"
 log ""
 cd "${IMMICH_WORKSPACE}/server" || (
-    log "Immich workspace not found"
+    log "Immich workspace not found"jj
     exit 1
 )
 
 while true; do
-    run_cmd node ./node_modules/.bin/nest start --debug "0.0.0.0:9230" --watch
+    run_cmd pnpm --filter immich exec nest start --debug "0.0.0.0:9230" --watch
     log "Nest API Server crashed with exit code $?.  Respawning in 3s ..."
     sleep 3
 done