refactor: make gitea a self-contained Cline skill

Relocate the script into the skill (skills/gitea/scripts/gitea_mcp.py) and add a
PEP 723 dependency block, so `uv run scripts/gitea_mcp.py` provisions deps with no
install step and the skill folder is portable (drop into ~/.cline/skills/). Drop
the non-standard `metadata` frontmatter — Cline only recognizes name + description.

- .mcp.json points at the relocated script and runs with --no-project (PEP 723)
- SKILL.md uses relative scripts/ paths; metadata block removed
- find_config walks up the tree to locate config.json (skill root or plugin root)
- tests import gitea_mcp via pytest pythonpath; README/CLAUDE paths updated

Tests: 119 passed, 92% coverage. Standalone list-tools verified via uv --no-project.

tests/unit/test_labels_milestones.py

@@ -2,7 +2,7 @@ import json
 import pytest
 import httpx
 import respx
-from server.gitea_mcp import (
+from gitea_mcp import (
     list_labels, create_label, add_issue_labels, list_milestones, create_milestone,
 )