feat(telemetry): Implement AI usage telemetry pattern and apply to add-task

This commit introduces a standardized pattern for capturing and propagating AI usage telemetry (cost, tokens, model used) across the Task Master stack and applies it to the 'add-task' functionality.

Key changes include:

- **Telemetry Pattern Definition:**
  - Added  defining the integration pattern for core logic, direct functions, MCP tools, and CLI commands.
  - Updated related rules (, ,
 Usage: mcp [OPTIONS] COMMAND [ARGS]...

 MCP development tools

╭─ Options ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╮
│ --help          Show this message and exit.                                                                                                │
╰────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯
╭─ Commands ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╮
│ version   Show the MCP version.                                                                                                            │
│ dev       Run a MCP server with the MCP Inspector.                                                                                         │
│ run       Run a MCP server.                                                                                                                │
│ install   Install a MCP server in the Claude desktop app.                                                                                  │
╰────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯, , ) to reference the new telemetry rule.

- **Core Telemetry Implementation ():**
  - Refactored the unified AI service to generate and return a  object alongside the main AI result.
  - Fixed an MCP server startup crash by removing redundant local loading of  and instead using the  imported from  for cost calculations.
  - Added  to the  object.

- ** Integration:**
  - Modified  (core) to receive  from the AI service, return it, and call the new UI display function for CLI output.
  - Updated  to receive  from the core function and include it in the  payload of its response.
  - Ensured  (MCP tool) correctly passes the  through via .
  - Updated  to correctly pass context (, ) to the core  function and rely on it for CLI telemetry display.

- **UI Enhancement:**
  - Added  function to  to show telemetry details in the CLI.

- **Project Management:**
  - Added subtasks 77.6 through 77.12 to track the rollout of this telemetry pattern to other AI-powered commands (, , , , , , ).

This establishes the foundation for tracking AI usage across the application.

src/ai-providers/anthropic.js

@@ -51,7 +51,7 @@ function getClient(apiKey) {
  * @param {Array<object>} params.messages - The messages array (e.g., [{ role: 'user', content: '...' }]).
  * @param {number} [params.maxTokens] - Maximum tokens for the response.
  * @param {number} [params.temperature] - Temperature for generation.
- * @returns {Promise<string>} The generated text content.
+ * @returns {Promise<object>} The generated text content and usage.
  * @throws {Error} If the API call fails.
  */
 export async function generateAnthropicText({
@@ -76,7 +76,14 @@ export async function generateAnthropicText({
 			'debug',
 			`Anthropic generateText result received. Tokens: ${result.usage.completionTokens}/${result.usage.promptTokens}`
 		);
-		return result.text;
+		// Return both text and usage
+		return {
+			text: result.text,
+			usage: {
+				inputTokens: result.usage.promptTokens,
+				outputTokens: result.usage.completionTokens
+			}
+		};
 	} catch (error) {
 		log('error', `Anthropic generateText failed: ${error.message}`);
 		// Consider more specific error handling or re-throwing a standardized error
@@ -160,7 +167,7 @@ export async function streamAnthropicText({
  * @param {number} [params.maxTokens] - Maximum tokens for the response.
  * @param {number} [params.temperature] - Temperature for generation.
  * @param {number} [params.maxRetries] - Max retries for validation/generation.
- * @returns {Promise<object>} The generated object matching the schema.
+ * @returns {Promise<object>} The generated object matching the schema and usage.
  * @throws {Error} If generation or validation fails.
  */
 export async function generateAnthropicObject({
@@ -204,7 +211,14 @@ export async function generateAnthropicObject({
 			'debug',
 			`Anthropic generateObject result received. Tokens: ${result.usage.completionTokens}/${result.usage.promptTokens}`
 		);
-		return result.object;
+		// Return both object and usage
+		return {
+			object: result.object,
+			usage: {
+				inputTokens: result.usage.promptTokens,
+				outputTokens: result.usage.completionTokens
+			}
+		};
 	} catch (error) {
 		// Simple error logging
 		log(