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.

.mcp.json

@@ -4,8 +4,8 @@
       "command": "uv",
       "args": [
         "run",
-        "--project", "${CLAUDE_PLUGIN_ROOT}",
-        "${CLAUDE_PLUGIN_ROOT}/server/gitea_mcp.py",
+        "--no-project",
+        "${CLAUDE_PLUGIN_ROOT}/skills/gitea/scripts/gitea_mcp.py",
         "--config", "${CLAUDE_PLUGIN_ROOT}/config.json"
       ]
     }