feat(issues): add dependency management commands

Add commands to manage issue dependencies using the Gitea API:
- `tea issues dependencies <index>` - list dependencies
- `tea issues dependencies add <index> <dep>` - add a dependency
- `tea issues dependencies remove <index> <dep>` - remove a dependency

Supports cross-repo dependencies with owner/repo#index syntax.
Supports all output formats (table, json, csv, etc.).

Closes #4

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

modules/api/client.go

@@ -97,3 +97,48 @@ func (c *Client) GetRaw(ctx context.Context, path string) ([]byte, error) {
 
 	return body, nil
 }
+
+// Post makes an authenticated POST request to the API and decodes the JSON response
+func (c *Client) Post(ctx context.Context, path string, body io.Reader, result interface{}) (*http.Response, error) {
+	return c.doRequest(ctx, "POST", path, body, result)
+}
+
+// Delete makes an authenticated DELETE request to the API
+func (c *Client) Delete(ctx context.Context, path string, body io.Reader) (*http.Response, error) {
+	return c.doRequest(ctx, "DELETE", path, body, nil)
+}
+
+// doRequest performs an HTTP request with the given method
+func (c *Client) doRequest(ctx context.Context, method, path string, body io.Reader, result interface{}) (*http.Response, error) {
+	url := fmt.Sprintf("%s/api/v1%s", c.login.URL, path)
+
+	req, err := http.NewRequestWithContext(ctx, method, url, body)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create request: %w", err)
+	}
+
+	req.Header.Set("Authorization", "token "+c.login.Token)
+	req.Header.Set("Accept", "application/json")
+	if body != nil {
+		req.Header.Set("Content-Type", "application/json")
+	}
+
+	resp, err := c.httpClient.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("failed to execute request: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode >= 400 {
+		respBody, _ := io.ReadAll(resp.Body)
+		return resp, fmt.Errorf("API request failed with status %d: %s", resp.StatusCode, string(respBody))
+	}
+
+	if result != nil {
+		if err := json.NewDecoder(resp.Body).Decode(result); err != nil {
+			return resp, fmt.Errorf("failed to decode response: %w", err)
+		}
+	}
+
+	return resp, nil
+}