feat: gitea connector #463

[sowen1023]

What does this PR do

• feat: gitea connector

Standards checklist

• The PR title is descriptive
• The commit messages are semantic
• Updated the release notes
• Necessary documents have been added if this is a new feature

[sowen1023]

Doc of example:

{
    "_index": "coco_document-v2",
    "_type": "_doc",
    "_id": "2d0b15469184d98b40296e0145590c75",
    "_score": 2.2306416,
    "_source": {
        "id": "2d0b15469184d98b40296e0145590c75",
        "created": "2025-08-10T06:54:14Z",
        "updated": "2025-08-10T06:54:14Z",
        "metadata": {
            "comments": 0,
            "id": 376544,
            "number": 468,
            "state": "open"
        },
        "source": {
            "type": "connector",
            "name": "Gitea Coco Server",
            "id": "d2tev2lafbiqoh2qok4g"
        },
        "type": "issue",
        "category": "sowen1023/coco-server",
        "title": "[Bug] API token list fails to support pagination",
        "content": "http://localhost:9001/#/api-token/list",
        "icon": "issue",
        "owner": {
            "avatar": "https://seccdn.libravatar.org/avatar/256956be770cf94989c2a842e3b500b0?d=identicon",
            "username": "sowen1023",
            "userid": "143295"
        },
        "url": "https://gitea.com/sowen1023/coco-server/issues/468",
        "size": 38
    }
}

[medcl]

the release note should be placed under the Latest section

[sowen1023]

Resolved

[medcl]

@sowen1023 fix the conflicts first.