Add 7 missing SDK methods and fix README type name

- Fix AgentKeyRequest → RegisterAgentKeyInput in README
- Add ListAgents, UnfreezeAgent, DeleteAgent to agents.go
- Add GetMe, IssueApiToken to auth.go
- Add DownloadExport to exports.go
- Add Health package-level function in health.go
- Add corresponding types and document all exports in README

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

agents.go

@@ -1,6 +1,9 @@
 package elydora
 
-import "fmt"
+import (
+	"fmt"
+	"net/http"
+)
 
 // RegisterAgent registers a new AI agent within the organization.
 func (c *Client) RegisterAgent(req *RegisterAgentRequest) (*RegisterAgentResponse, error) {
@@ -34,3 +37,28 @@ func (c *Client) RevokeKey(agentID, kid, reason string) error {
 		Reason: reason,
 	}, nil)
 }
+
+// ListAgents retrieves all agents for the organization.
+func (c *Client) ListAgents() (*ListAgentsResponse, error) {
+	var result ListAgentsResponse
+	if err := c.doGet("/v1/agents", &result); err != nil {
+		return nil, err
+	}
+	return &result, nil
+}
+
+// UnfreezeAgent unfreezes a previously frozen agent.
+func (c *Client) UnfreezeAgent(agentID, reason string) error {
+	return c.doPost(fmt.Sprintf("/v1/agents/%s/unfreeze", agentID), &UnfreezeAgentRequest{
+		Reason: reason,
+	}, nil)
+}
+
+// DeleteAgent permanently deletes an agent and all associated data.
+func (c *Client) DeleteAgent(agentID string) (*DeleteAgentResponse, error) {
+	var result DeleteAgentResponse
+	if err := c.doRequest(http.MethodDelete, fmt.Sprintf("/v1/agents/%s", agentID), nil, &result); err != nil {
+		return nil, err
+	}
+	return &result, nil
+}