[fix] cubes: service:autostart reads its data, and its README describes it

Closes DOCS-AUDIT §6.1 and §5.1.

**The script could not run.** It read `APP` off `host.data` and then used
`SERVICE_NAME` and `AUTOSTART` as if they were in scope, so the very first
statement — `if AUTOSTART:` — raised `NameError`; `server` was used in the else
branch but never imported. Three lines: import `server` alongside `systemd`,
read the two names next to `APP`. The logic underneath was always right.
`python3 -m py_compile` passes.

**The README documented a different cube.** It was titled "TypeStack Install
Cube" and described cloning a git repository, `yarn install`, `yarn build`,
`docker compose up -d` and PM2 — none of which this cube does, and it listed
parameters (`USER`, `REPO`, `ENV`, `NODE_PATH`) the manifest does not have,
carrying someone's private repository URL and username as defaults.

Rewritten from the manifest and the now-working script: the three parameters
that exist, and the thing the old text obscured by describing a deploy
pipeline — this cube does not create the unit file, it enables and starts one
that is already installed. `SERVICE_NAME` is documented as what it is, a label
that never reaches systemd, so getting it wrong is cosmetic rather than a cube
managing the wrong unit.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DCzYTAm9QUhvLNr2EpdagJ

packages/nopy-cubes-core/cubes/service/autostart/deploy.py

@@ -1,8 +1,10 @@
-from pyinfra.operations import systemd
+from pyinfra.operations import server, systemd
 from pyinfra import host
 
 
 APP = host.data.APP
+SERVICE_NAME = host.data.SERVICE_NAME
+AUTOSTART = host.data.AUTOSTART
 
 # Enable and start the service based on AUTOSTART flag
 if AUTOSTART:
@@ -24,4 +26,4 @@ else:
         name=f'Service {SERVICE_NAME} created but not enabled (AUTOSTART=False)',
         commands=[f'echo "Service {SERVICE_NAME} is ready but not started. Enable with: sudo systemctl enable {APP} && sudo systemctl start {APP}"'],
         _sudo=False
-    )
+    )