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 🏄🏻‍♂️

cli/testdata/coder_--help.golden

@@ -53,6 +53,7 @@ SUBCOMMANDS:
     stop              Stop a workspace
     support           Commands for troubleshooting issues with a Coder
                       deployment.
+    task              Manage tasks
     templates         Manage templates
     tokens            Manage personal access tokens
     unfavorite        Remove a workspace from your favorites

cli/testdata/coder_task_--help.golden

@@ -0,0 +1,19 @@
+coder v0.0.0-devel
+
+USAGE:
+  coder task
+
+  Manage tasks
+
+  Aliases: tasks
+
+SUBCOMMANDS:
+    create    Create a task
+    delete    Delete tasks
+    list      List tasks
+    logs      Show a task's logs
+    send      Send input to a task
+    status    Show the status of a task.
+
+———
+Run `coder --help` for a list of global options.

cli/testdata/coder_task_create_--help.golden

@@ -0,0 +1,51 @@
+coder v0.0.0-devel
+
+USAGE:
+  coder task create [flags] [input]
+
+  Create a task
+
+    - 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:
+  -O, --org string, $CODER_ORGANIZATION
+          Select which organization (uuid or name) to use.
+
+      --name string
+          Specify the name of the task. If you do not specify one, a name will
+          be generated for you.
+
+      --owner string (default: me)
+          Specify the owner of the task. Defaults to the current user.
+
+      --preset string, $CODER_TASK_PRESET_NAME (default: none)
+  -q, --quiet bool
+          Only display the created task's ID.
+
+      --stdin bool
+          Reads from stdin for the task input.
+
+      --template string, $CODER_TASK_TEMPLATE_NAME
+      --template-version string, $CODER_TASK_TEMPLATE_VERSION
+———
+Run `coder --help` for a list of global options.

cli/testdata/coder_task_delete_--help.golden

@@ -0,0 +1,27 @@
+coder v0.0.0-devel
+
+USAGE:
+  coder task delete [flags] <task> [<task> ...]
+
+  Delete tasks
+
+  Aliases: rm
+
+    - Delete a single task.:
+  
+       $ $ coder task delete task1
+  
+    - Delete multiple tasks.:
+  
+       $ $ coder task delete task1 task2 task3
+  
+    - Delete a task without confirmation.:
+  
+       $ $ coder task delete task4 --yes
+
+OPTIONS:
+  -y, --yes bool
+          Bypass prompts.
+
+———
+Run `coder --help` for a list of global options.

cli/testdata/coder_task_list_--help.golden

@@ -0,0 +1,50 @@
+coder v0.0.0-devel
+
+USAGE:
+  coder task list [flags]
+
+  List tasks
+
+  Aliases: ls
+
+    - List tasks for the current user.:
+  
+       $ coder task list
+  
+    - List tasks for a specific user.:
+  
+       $ coder task list --user someone-else
+  
+    - List all tasks you can view.:
+  
+       $ coder task list --all
+  
+    - List all your running tasks.:
+  
+       $ coder task list --status running
+  
+    - As above, but only show IDs.:
+  
+       $ coder task list --status running --quiet
+
+OPTIONS:
+  -a, --all bool (default: false)
+          List tasks for all users you can view.
+
+  -c, --column [id|organization id|owner id|owner name|owner avatar url|name|display name|template id|template version id|template name|template display name|template icon|workspace id|workspace name|workspace status|workspace build number|workspace agent id|workspace agent lifecycle|workspace agent health|workspace app id|initial prompt|status|state|message|created at|updated at|state changed] (default: name,status,state,state changed,message)
+          Columns to display in table output.
+
+  -o, --output table|json (default: table)
+          Output format.
+
+  -q, --quiet bool (default: false)
+          Only display task IDs.
+
+      --status pending|initializing|active|paused|error|unknown
+          Filter by task status.
+
+      --user string
+          List tasks for the specified user (username, "me").
+
+———
+Run `coder --help` for a list of global options.

cli/testdata/coder_task_logs_--help.golden

@@ -0,0 +1,20 @@
+coder v0.0.0-devel
+
+USAGE:
+  coder task logs [flags] <task>
+
+  Show a task's logs
+
+    - Show logs for a given task.:
+  
+       $ coder task logs task1
+
+OPTIONS:
+  -c, --column [id|content|type|time] (default: type,content)
+          Columns to display in table output.
+
+  -o, --output table|json (default: table)
+          Output format.
+
+———
+Run `coder --help` for a list of global options.

cli/testdata/coder_task_send_--help.golden

@@ -0,0 +1,21 @@
+coder v0.0.0-devel
+
+USAGE:
+  coder task send [flags] <task> [<input> | --stdin]
+
+  Send input to a task
+
+    - Send direct input to a task.:
+  
+       $ coder task send task1 "Please also add unit tests"
+  
+    - Send input from stdin to a task.:
+  
+       $ echo "Please also add unit tests" | coder task send task1 --stdin
+
+OPTIONS:
+      --stdin bool
+          Reads the input from stdin.
+
+———
+Run `coder --help` for a list of global options.

cli/testdata/coder_task_status_--help.golden

@@ -0,0 +1,30 @@
+coder v0.0.0-devel
+
+USAGE:
+  coder task status [flags]
+
+  Show the status of a task.
+
+  Aliases: stat
+
+    - Show the status of a given task.:
+  
+       $ coder task status task1
+  
+    - Watch the status of a given task until it completes (idle or stopped).:
+  
+       $ coder task status task1 --watch
+
+OPTIONS:
+  -c, --column [id|organization id|owner id|owner name|owner avatar url|name|display name|template id|template version id|template name|template display name|template icon|workspace id|workspace name|workspace status|workspace build number|workspace agent id|workspace agent lifecycle|workspace agent health|workspace app id|initial prompt|status|state|message|created at|updated at|state changed|healthy] (default: state changed,status,healthy,state,message)
+          Columns to display in table output.
+
+  -o, --output table|json (default: table)
+          Output format.
+
+      --watch bool (default: false)
+          Watch the task status output. This will stream updates to the terminal
+          until the underlying workspace is stopped.
+
+———
+Run `coder --help` for a list of global options.