Consolidate tools from 110 to 45 using method dispatch (#143)

Consolidate 110 individual MCP tools down to 45 using a method dispatch pattern, aligning tool names with the GitHub MCP server conventions.

**Motivation:** LLMs work better with fewer, well-organized tools. The method dispatch pattern (used by GitHub's MCP server) groups related operations under read/write tools with a `method` parameter.

**Changes:**
- Group related tools into `_read`/`_write` pairs with method dispatch (e.g. `issue_read`, `issue_write`, `pull_request_read`, `pull_request_write`)
- Rename tools to match GitHub MCP naming (`get_file_contents`, `create_or_update_file`, `list_issues`, `list_pull_requests`, etc.)
- Rename `pageSize` to `perPage` for GitHub MCP compat
- Move issue label ops (`add_labels`, `remove_label`, etc.) into `issue_write`
- Merge `create_file`/`update_file` into `create_or_update_file` with optional `sha`
- Make `delete_file` require `sha`
- Add `get_labels` method to `issue_read`
- Add shared helpers: `GetInt64Slice`, `GetStringSlice`, `GetPagination` in params package
- Unexport all dispatch handler functions
- Fix: pass assignees/milestone in `CreateIssue`, bounds check in `GetFileContent`

Reviewed-on: https://gitea.com/gitea/gitea-mcp/pulls/143
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: silverwind <me@silverwind.io>
Co-committed-by: silverwind <me@silverwind.io>

pkg/params/params.go

@@ -41,9 +41,9 @@ func GetStringSlice(args map[string]any, key string) []string {
 	return out
 }
 
-// GetPagination extracts page and pageSize parameters, returning them as ints.
+// GetPagination extracts page and perPage parameters, returning them as ints.
 func GetPagination(args map[string]any, defaultPageSize int64) (page, pageSize int) {
-	return int(GetOptionalInt(args, "page", 1)), int(GetOptionalInt(args, "pageSize", defaultPageSize))
+	return int(GetOptionalInt(args, "page", 1)), int(GetOptionalInt(args, "perPage", defaultPageSize))
 }
 
 // ToInt64 converts a value to int64, accepting both float64 (JSON number) and
@@ -84,6 +84,23 @@ func GetIndex(args map[string]any, key string) (int64, error) {
 	return 0, fmt.Errorf("%s must be a number or numeric string", key)
 }
 
+// GetInt64Slice extracts a required int64 slice parameter from MCP tool arguments.
+func GetInt64Slice(args map[string]any, key string) ([]int64, error) {
+	raw, ok := args[key].([]any)
+	if !ok {
+		return nil, fmt.Errorf("%s (array of IDs) is required", key)
+	}
+	out := make([]int64, 0, len(raw))
+	for _, v := range raw {
+		id, ok := ToInt64(v)
+		if !ok {
+			return nil, fmt.Errorf("invalid ID in %s array", key)
+		}
+		out = append(out, id)
+	}
+	return out, nil
+}
+
 // GetOptionalInt extracts an optional integer parameter from MCP tool arguments.
 // Returns defaultVal if the key is missing or the value cannot be parsed.
 // Accepts both float64 (JSON number) and string representations.