fix: CI/CD — move web build to CI, VPS only deploys (no build on VPS)

- ci.yml: add web build step + upload .next as artifact
- deploy.yml: download artifact via SCP, copy to VPS .next dir
  (no bun run build on VPS — only git pull + install + index + restart)
- Bump actions/checkout@v4 → @v5 (Node 20 deprecation)
- Revert next.config standalone mode (not needed for .next/ copy approach)
- Remove broken bun --cwd (doesn't support --cwd flag)

.hermes/plans/nix-deploy.md

@@ -0,0 +1,35 @@
+# Phase 15 — Nix-based CI/CD for mcpedia-web
+
+> User: "ci nya juga benarkan lah masa build di vps,harusnya kan di vps hanya deploy, dan seharusnya pakai nix"
+
+## Current State
+- Deploy workflow builds the web app ON the VPS via SSH (`cd apps/web && bun run build`)
+- mcpedia-web service runs directly from git checkout (`/home/code/mcpedia/apps/web/.next`)
+- No flake.nix in the repo
+- Other services (zeavis-*, gmw-*) are nix-deployed via `/nix/var/nix/profiles/<name>`
+
+## Goal
+- **CI**: builds the web app into a Nix store path
+- **Deploy**: VPS only copies + switches profiles (no build on VPS)
+
+## Approach: `nix build` + `nix copy` (push deployment)
+
+### 1. Add flake.nix to mcpedia repo
+Build the Next.js production output into a Nix package:
+- `next build` outputs to `.next/`
+- Package: a shell script that runs `next start` with the `.next` dir + `node_modules`
+
+### 2. CI workflow (`ci.yml`)
+- Add a `nix build` step after typecheck/test
+- Push the result to the VPS via `nix copy --ssh`
+
+### 3. Deploy workflow (`deploy.yml`)
+- Trigger on CI success
+- `nix copy` the built package to VPS
+- `nix profile install` / `systemctl restart` on VPS
+- No `bun run build` on VPS
+
+## Files to create/modify
+- `flake.nix` (new) — builds @mcpedia/web as a Nix package
+- `.github/workflows/ci.yml` — add nix build step
+- `.github/workflows/deploy.yml` — nix copy + profile switch instead of SSH build