refactor(claude): use built-in node user instead of custom claude user

Drop the addgroup/adduser layer entirely. node:20-alpine already ships
a node user at uid/gid 1000. Update chown and USER directives, and
update the claude-config volume mount path to /home/node/.claude.

CLAUDE.md

@@ -10,8 +10,8 @@ This file provides context and guidance for working with this project.
 
 Three containers managed by Docker Compose:
 
-- **`claude`** — Claude Code CLI (`node:20-alpine`), non-root (UID 1000), isolated to an internal-only Docker network
-- **`webui`** — Claude Code as a browser terminal via ttyd (`node:20-alpine`), non-root (UID 1000), same network isolation, basic auth required
+- **`claude`** — Claude Code CLI (`node:20-alpine`), runs as the built-in `node` user (UID 1000), isolated to an internal-only Docker network
+- **`webui`** — Claude Code as a browser terminal via ttyd (`node:20-alpine`), `node` user (UID 1000), same network isolation, basic auth required
 - **`proxy`** — Squid forward proxy (`alpine:3.21`), `squid` user, bridges the internal network to the internet with an egress allowlist
 
 Key Docker network property: `claude-internal` has `internal: true`, meaning Docker adds no default gateway. The `claude` and `webui` containers physically cannot reach the internet without going through the `proxy` container.

README.md

@@ -30,8 +30,8 @@ Runs [Claude Code](https://claude.ai/code) inside an isolated Docker environment
 └──────────────────────────────────────────────────────────┘
 ```
 
-- **`claude`** — Claude Code CLI (`node:20-alpine`), UID 1000, on `claude-internal` only
-- **`webui`** — Claude Code in a browser terminal via ttyd (`node:20-alpine`), UID 1000, on `claude-internal` only, port 7681
+- **`claude`** — Claude Code CLI (`node:20-alpine`), runs as the built-in `node` user (UID 1000), on `claude-internal` only
+- **`webui`** — Claude Code in a browser terminal via ttyd (`node:20-alpine`), `node` user (UID 1000), on `claude-internal` only, port 7681
 - **`proxy`** — Squid forward proxy (`alpine:3.21`), bridges `claude-internal` ↔ internet with egress allowlist
 - **`claude-internal`** — `internal: true`; no default gateway, containers cannot reach the internet directly
 - **`proxy-external`** — Standard bridge; proxy sidecar only
@@ -161,7 +161,7 @@ Rebuild after changes:
 
 | Control | claude / webui | proxy |
 |---|---|---|
-| Non-root user | UID 1000 (`claude`) | `squid` user |
+| Non-root user | UID 1000 (`node`, built into base image) | `squid` user |
 | `no-new-privileges` | yes | yes |
 | All capabilities dropped | yes | yes |
 | Direct internet access | no (`internal` network only) | allowlisted only |

claude/Dockerfile

@@ -11,21 +11,17 @@ RUN apk add --no-cache \
 # Entrypoint used by the webui service (ttyd wrapping claude)
 COPY --chmod=755 webui-entrypoint.sh /usr/local/bin/webui-entrypoint.sh
 
-# Create non-root user (node:20-alpine reserves gid/uid 1000 for the node user)
-RUN addgroup -g 1001 claude \
-    && adduser -u 1001 -G claude -s /bin/bash -D claude
-
-# Install Claude Code globally (runs as root for npm -g, then drops)
+# Install Claude Code globally
 RUN npm install -g @anthropic-ai/claude-code
 
-# Workspace and Claude config dir — both owned by claude user.
+# Workspace and Claude config dir — owned by the built-in node user (uid 1000).
 # Pre-creating ~/.claude ensures the named volume is initialised with the
 # correct ownership when first mounted (Docker copies image content into
 # an empty named volume on first use).
-RUN mkdir -p /workspace /home/claude/.claude \
-    && chown -R claude:claude /workspace /home/claude/.claude
+RUN mkdir -p /workspace /home/node/.claude \
+    && chown -R node:node /workspace /home/node/.claude
 
-USER claude
+USER node
 WORKDIR /workspace
 
 # Proxy traffic through sidecar — override at runtime if needed

docker-compose.yml

@@ -43,7 +43,7 @@ services:
       # OAuth callback — required for browser-based login (claude login)
       - "0.0.0.0:54545:54545"
     volumes:
-      - claude-config:/home/claude/.claude
+      - claude-config:/home/node/.claude
       # Workspace is injected by claude.sh via --volume flag at run time.
       # Default: named Docker volume. Override: set WORKSPACE_DIR on the host.
     security_opt:
@@ -82,7 +82,7 @@ services:
       # OAuth callback — required for browser-based login (claude login)
       - "0.0.0.0:54545:54545"
     volumes:
-      - claude-config:/home/claude/.claude
+      - claude-config:/home/node/.claude
       - claude-web-workspace:/workspace
     security_opt:
       - no-new-privileges:true