Add sorting, user assignment, and UI improvements

Features:
- Add work item sorting by ID, Type, State (keys 1, 2, 3)
- Add user assignment modal with team member filtering (key a)
- Add parent work item title display in details panel
- Preserve sort order and selection on panel reload

UI improvements:
- Remove zebra striping from work items list
- Remove priority column from list and details
- Align metadata fields in details panel
- Add markdown rendering for descriptions (using glamour)
- Add state colors: To Do (orange), In Progress (purple), Done (green), Testing (yellow)

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

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

internal/api/teams.go

@@ -0,0 +1,51 @@
+package api
+
+import (
+	"fmt"
+
+	"github.com/samuelenocsson/devops-tui/internal/models"
+)
+
+// teamMembersResponse represents the response from team members API
+type teamMembersResponse struct {
+	Value []teamMemberItem `json:"value"`
+	Count int              `json:"count"`
+}
+
+type teamMemberItem struct {
+	Identity identityRef `json:"identity"`
+}
+
+type identityRef struct {
+	DisplayName string `json:"displayName"`
+	UniqueName  string `json:"uniqueName"`
+	ID          string `json:"id"`
+}
+
+// GetTeamMembers fetches all members of the configured team
+func (c *Client) GetTeamMembers() ([]models.TeamMember, error) {
+	// Azure DevOps API: GET https://dev.azure.com/{org}/_apis/projects/{project}/teams/{team}/members
+	url := fmt.Sprintf("https://dev.azure.com/%s/_apis/projects/%s/teams/%s/members?api-version=%s",
+		c.organization, c.project, c.team, apiVersion)
+
+	resp, err := c.doRequest("GET", url, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	var apiResp teamMembersResponse
+	if err := decode(resp, &apiResp); err != nil {
+		return nil, err
+	}
+
+	members := make([]models.TeamMember, 0, len(apiResp.Value))
+	for _, item := range apiResp.Value {
+		members = append(members, models.TeamMember{
+			ID:          item.Identity.ID,
+			DisplayName: item.Identity.DisplayName,
+			UniqueName:  item.Identity.UniqueName,
+		})
+	}
+
+	return members, nil
+}