No zeronet.conf available

### Step 1: Please describe your environment

* ZeroNet version: 0.6.0
* Operating system: NixOS

### Step 2: Describe the problem:

Trying to package zeronet, but cannot start as there is no `zeronet.conf` and there is also no template on how such a file should look like

#### Observed Results:

* zeronet fails to start:

```
- Starting ZeroNet...
ERROR:root:Unhandled exception: [Errno 30] Read-only file system: 'log'
Traceback (most recent call last):
File "/nix/store/3p5qvhnblipf23v4326cg9kg0pph459r-zeronet-0.6.0/bin/.zeronet.py-wrapped", line 19, in main
import main
File "/nix/store/3p5qvhnblipf23v4326cg9kg0pph459r-zeronet-0.6.0/bin/src/main.py", line 32, in
os.mkdir(config.log_dir)
OSError: [Errno 30] Read-only file system: 'log'
Traceback (most recent call last):
File "/nix/store/3p5qvhnblipf23v4326cg9kg0pph459r-zeronet-0.6.0/bin/.zeronet.py-wrapped", line 92, in
main()
File "/nix/store/3p5qvhnblipf23v4326cg9kg0pph459r-zeronet-0.6.0/bin/.zeronet.py-wrapped", line 65, in main
traceback.print_exc(file=open(config.log_dir + "/error.log", "a"))
IOError: [Errno 2] No such file or directory: 'log/error.log'
```

#### Expected Results:

* zeronet should start

Start with src/main.py and the startup wrapper shown in the traceback; inspect how config.log_dir is selected and how packaged launches handle writable paths. Reproduce the NixOS startup failure, then provide or document a zeronet.conf template and startup behavior that lets a packaged instance start without writing to the read-only store. Verify that startup and error logging work in the packaged environment.

由索引模型根据 Issue 内容生成。