docs: Update documentation for new AI/config architecture and finalize cleanup

This commit updates all relevant documentation (READMEs, docs/*, .cursor/rules) to accurately reflect the finalized unified AI service architecture and the new configuration system (.taskmasterconfig + .env/mcp.json). It also includes the final code cleanup steps related to the refactoring.

Key Changes:

1.  **Documentation Updates:**

    *   Revised `README.md`, `README-task-master.md`, `assets/scripts_README.md`, `docs/configuration.md`, and `docs/tutorial.md` to explain the new configuration split (.taskmasterconfig vs .env/mcp.json).

    *   Updated MCP configuration examples in READMEs and tutorials to only include API keys in the `env` block.

    *   Added/updated examples for using the `--research` flag in `docs/command-reference.md`, `docs/examples.md`, and `docs/tutorial.md`.

    *   Updated `.cursor/rules/ai_services.mdc`, `.cursor/rules/architecture.mdc`, `.cursor/rules/dev_workflow.mdc`, `.cursor/rules/mcp.mdc`, `.cursor/rules/taskmaster.mdc`, `.cursor/rules/utilities.mdc`, and `.cursor/rules/new_features.mdc` to align with the new architecture, removing references to old patterns/files.

    *   Removed internal rule links from user-facing rules (`taskmaster.mdc`, `dev_workflow.mdc`, `self_improve.mdc`).

    *   Deleted outdated example file `docs/ai-client-utils-example.md`.

2.  **Final Code Refactor & Cleanup:**

    *   Corrected `update-task-by-id.js` by removing the last import from the old `ai-services.js`.

    *   Refactored `update-subtask-by-id.js` to correctly use the unified service and logger patterns.

    *   Removed the obsolete export block from `mcp-server/src/core/task-master-core.js`.

    *   Corrected logger implementation in `update-tasks.js` for CLI context.

    *   Updated API key mapping in `config-manager.js` and `ai-services-unified.js`.

3.  **Configuration Files:**

    *   Updated API keys in `.cursor/mcp.json`, replacing `GROK_API_KEY` with `XAI_API_KEY`.

    *   Updated `.env.example` with current API key names.

    *   Added `azureOpenaiBaseUrl` to `.taskmasterconfig` example.

4.  **Task Management:**

    *   Marked documentation subtask 61.10 as 'done'.

    *   Includes various other task content/status updates from the diff summary.

5.  **Changeset:**

    *   Added `.changeset/cuddly-zebras-matter.md` for user-facing `expand`/`expand-all` improvements.

This commit concludes the major architectural refactoring (Task 61) and ensures the documentation accurately reflects the current system.

docs/command-reference.md

@@ -52,6 +52,9 @@ task-master show 1.2
 ```bash
 # Update tasks from a specific ID and provide context
 task-master update --from=<id> --prompt="<prompt>"
+
+# Update tasks using research role
+task-master update --from=<id> --prompt="<prompt>" --research
 ```
 
 ## Update a Specific Task
@@ -60,7 +63,7 @@ task-master update --from=<id> --prompt="<prompt>"
 # Update a single task by ID with new information
 task-master update-task --id=<id> --prompt="<prompt>"
 
-# Use research-backed updates with Perplexity AI
+# Use research-backed updates
 task-master update-task --id=<id> --prompt="<prompt>" --research
 ```
 
@@ -73,7 +76,7 @@ task-master update-subtask --id=<parentId.subtaskId> --prompt="<prompt>"
 # Example: Add details about API rate limiting to subtask 2 of task 5
 task-master update-subtask --id=5.2 --prompt="Add rate limiting of 100 requests per minute"
 
-# Use research-backed updates with Perplexity AI
+# Use research-backed updates
 task-master update-subtask --id=<parentId.subtaskId> --prompt="<prompt>" --research
 ```
 
@@ -187,9 +190,12 @@ task-master fix-dependencies
 ## Add a New Task
 
 ```bash
-# Add a new task using AI
+# Add a new task using AI (main role)
 task-master add-task --prompt="Description of the new task"
 
+# Add a new task using AI (research role)
+task-master add-task --prompt="Description of the new task" --research
+
 # Add a task with dependencies
 task-master add-task --prompt="Description" --dependencies=1,2,3