Bug: Composer dependency constraints allow incompatible CodeIgniter versions

## Summary

A fresh installation of SmartyURL using:

```bash
composer create-project extendy/smartyurl public
```

fails because the current dependency constraints allow Composer to consider incompatible CodeIgniter versions.

SmartyURL currently requires:

```json
"codeigniter4/framework": "^4.3",
"psr/log": "^1.1"
```

The `^4.3` constraint allows CodeIgniter releases from `4.3.0` up to, but not including, `5.0.0`, including recent releases such as CodeIgniter 4.7.x.

However, newer CodeIgniter releases require `psr/log ^3.0`, while SmartyURL explicitly requires `psr/log ^1.1`. This causes Composer dependency resolution to fail during a clean installation.

## Installation environment

- Debian 13
- PHP 8.4
- Composer 2
- SmartyURL 1.0.0

## Steps to reproduce

Run:

```bash
composer create-project extendy/smartyurl public
```

Composer reports a dependency conflict involving:

```text
codeigniter4/framework
psr/log
```

## What happened during manual troubleshooting

Changing the SmartyURL requirement from:

```json
"psr/log": "^1.1"
```

to:

```json
"psr/log": "^3.0"
```

allowed Composer to install CodeIgniter 4.7.4.

However, the current SmartyURL application files are not fully compatible with CodeIgniter 4.7.4. Additional runtime errors then occurred, including:

```text
Undefined property: Config\App::$permittedURIChars
```

The following application entry files also had to be replaced with newer framework-compatible versions:

- `spark`
- `public/index.php`

This confirms that simply upgrading the `psr/log` requirement is not a sufficient fix.

## Expected behaviour

A clean installation should install a CodeIgniter version that SmartyURL has been developed and tested against, without requiring manual dependency changes or framework compatibility patches.

## Proposed fix

The project should use a more restrictive CodeIgniter version constraint that reflects the version series currently supported by SmartyURL.

For example:

```json
"codeigniter4/framework": "4.3.*"
```

Alternatively, the exact tested release could be pinned, for example:

```json
"codeigniter4/framework": "4.3.8"
```

The actual constraint should be selected after confirming the CodeIgniter version originally used and tested with SmartyURL.

The compatibility of the direct `psr/log` requirement should also be reviewed. If SmartyURL does not directly depend on a specific `psr/log` major version, the explicit requirement may need to be removed or adjusted.

Where appropriate for this application, a tested `composer.lock` file should also be maintained so that installations resolve to known-compatible dependency versions.

## Additional recommendation

Add a clean-install CI workflow that runs commands such as:

```bash
composer install
php spark
php spark migrate --all
```

This would help detect dependency-resolution and framework-compatibility issues before publishing a release.

## Impact

This issue currently prevents a standard clean installation of SmartyURL 1.0.0.

Users who attempt to resolve the Composer conflict by upgrading `psr/log` may unintentionally install a newer CodeIgniter release that is incompatible with the current SmartyURL application files.