Add source in composer package

[lutek]

Feature Description

Add source in composer package. Package can be linked with repository, should be used as source.
https://getcomposer.org/doc/05-repositories.md#package

Source: The source is used for development. This will usually originate from a source code repository, such as git. You can fetch this when you want to modify the downloaded package.

On 'composer show' i get empty source, even though composer.json specifies preferred source for selected package.

composer.json

    "config": {
        "optimize-autoloader": true,
        "sort-packages": true,
        "preferred-install": {
            "ecommercebox/*": "source"
        }
    },

❯ composer show ecommercebox/sw-plugin-xxx
name     : ecommercebox/sw-plugin-xxx
descrip. : xxx Shops API
keywords : 
versions : * x.x.x
released : 2024-12-31, today
type     : shopware-platform-plugin
license  : proprietary
homepage : 
source   : []  
dist     : [zip] https://xxx.xxx/api/packages/shopware/composer/files/ecommercebox%2Fsw-plugin-xxx/x.x.x/ecommercebox-sw-plugin-xxx.x.x.x.zip 
path     : /Users/lutek/www/xxx.local/vendor/ecommercebox/sw-plugin-xxx
names    : ecommercebox/sw-plugin-xxx

Screenshots

No response

[iVegas]

Related #20871

[iVegas]

The structure requires an update here:
https://github.com/go-gitea/gitea/blob/main/routers/api/packages/composer/api.go#L69

[lunny]

I sent #33502 to resolve this, please help to review.