feat(cli): promote tasks commands from experimental to GA (#20916)

## Overview

This change promotes the tasks CLI commands from `coder exp task` to
`coder task`, marking them as generally available (GA).

## Migration

Users will need to update their scripts from:

```shell
coder exp task create "my task"
```

To:
```shell
coder task create "my task"
```

---

🤖 This change was written by Claude Sonnet 4.5 Thinking using [mux](https://github.com/coder/mux) and reviewed by a human 🏄🏻‍♂️

docs/reference/cli/task_create.md

@@ -0,0 +1,100 @@
+<!-- DO NOT EDIT | GENERATED CONTENT -->
+# task create
+
+Create a task
+
+## Usage
+
+```console
+coder task create [flags] [input]
+```
+
+## Description
+
+```console
+  - Create a task with direct input:
+
+     $ coder task create "Add authentication to the user service"
+
+  - Create a task with stdin input:
+
+     $ echo "Add authentication to the user service" | coder task create
+
+  - Create a task with a specific name:
+
+     $ coder task create --name task1 "Add authentication to the user service"
+
+  - Create a task from a specific template / preset:
+
+     $ coder task create --template backend-dev --preset "My Preset" "Add authentication to the user service"
+
+  - Create a task for another user (requires appropriate permissions):
+
+     $ coder task create --owner user@example.com "Add authentication to the user service"
+```
+
+## Options
+
+### --name
+
+|      |                     |
+|------|---------------------|
+| Type | <code>string</code> |
+
+Specify the name of the task. If you do not specify one, a name will be generated for you.
+
+### --owner
+
+|         |                     |
+|---------|---------------------|
+| Type    | <code>string</code> |
+| Default | <code>me</code>     |
+
+Specify the owner of the task. Defaults to the current user.
+
+### --template
+
+|             |                                        |
+|-------------|----------------------------------------|
+| Type        | <code>string</code>                    |
+| Environment | <code>$CODER_TASK_TEMPLATE_NAME</code> |
+
+### --template-version
+
+|             |                                           |
+|-------------|-------------------------------------------|
+| Type        | <code>string</code>                       |
+| Environment | <code>$CODER_TASK_TEMPLATE_VERSION</code> |
+
+### --preset
+
+|             |                                      |
+|-------------|--------------------------------------|
+| Type        | <code>string</code>                  |
+| Environment | <code>$CODER_TASK_PRESET_NAME</code> |
+| Default     | <code>none</code>                    |
+
+### --stdin
+
+|      |                   |
+|------|-------------------|
+| Type | <code>bool</code> |
+
+Reads from stdin for the task input.
+
+### -q, --quiet
+
+|      |                   |
+|------|-------------------|
+| Type | <code>bool</code> |
+
+Only display the created task's ID.
+
+### -O, --org
+
+|             |                                  |
+|-------------|----------------------------------|
+| Type        | <code>string</code>              |
+| Environment | <code>$CODER_ORGANIZATION</code> |
+
+Select which organization (uuid or name) to use.