Milestone addition and Windows build support (#104)

## Milestone Implementation

The `milestone.go` file adds comprehensive milestone functionality to the Gitea MCP server with the following MCP tools:

### Tools Added:

1. __`get_milestone`__ - Retrieves a specific milestone by ID
2. __`list_milestones`__ - Lists repository milestones with filtering options
3. __`create_milestone`__ - Creates new milestones with title, description, and due dates
4. __`edit_milestone`__ - Modifies existing milestones including state changes
5. __`delete_milestone`__ - Removes milestones from repositories

### Integration with Other Components:

__Issue Management__:

- Issues can be associated with milestones through the `edit_issue` tool
- The `milestone` parameter (number) links issues to specific milestones
- This creates traceability between development tasks and project milestones

__Pull Request Filtering__:

- Pull requests can be filtered by milestone using the `milestone` parameter
- This enables viewing all PRs related to a specific milestone

### Key Features:

- __State Management__: Milestones support "open" and "closed" states
- __Due Dates__: Optional due dates for milestone tracking
- __Pagination__: List operations support pagination for large datasets
- __Full CRUD Operations__: Complete create, read, update, delete capabilities

### Workflow Integration:

While there's no direct commit message integration shown in the current implementation, milestones provide project planning capabilities that integrate with:

- Issue tracking (linking issues to milestones)
- Development workflow (filtering PRs by milestone)
- Project management (due dates, state tracking)

This addition enables project management capabilities within the Gitea MCP server, allowing users to organize work into milestones and track progress across issues and pull requests.

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feat: add Windows build support with PowerShell and batch scripts

Add comprehensive Windows build support including PowerShell script (build.ps1) and batch wrapper (build.bat) that replicate Makefile functionality. The scripts provide targets for building, installing, cleaning, and development with hot reload support. Also includes detailed BUILDING.md documentation for Windows users.

Co-authored-by: hiifong <i@hiif.ong>
Reviewed-on: https://gitea.com/gitea/gitea-mcp/pulls/104
Reviewed-by: hiifong <i@hiif.ong>
Co-authored-by: Nassim Amar <namar0x0309@pm.me>
Co-committed-by: Nassim Amar <namar0x0309@pm.me>

build.bat

@@ -0,0 +1,2 @@
+@echo off
+powershell -ExecutionPolicy Bypass -File "%~dp0build.ps1" %*