Clean up cvd help, remove deprecated commands, and refactor

- Hide irrelevant commands in cvd help by default.
- Delete noop.cpp and noop.h (removing kill-server, server-kill, restart-server).
- Clean up help strings and TopLevelHelp logic in help.cpp.

Output without a running device:
================================
```
Cuttlefish Virtual Device (CVD) CLI.

usage: cvd <selector/driver options> <command> <args>

Driver Options:
  -help                  Print this message
  -verbosity=<LEVEL>     Adjust Cvd verbosity level. LEVEL is Android log
                         severity. (Required: cvd >= v1.3)

Commands (cvd help <command> for more information):

        cache - Manage the files cached by cvd

        create - Create a Cuttlefish virtual device or environment

        fetch, fetch_cvd - Retrieve build artifacts based on branch and target names

        help - Used to display help information for other commands

        lint - error checks the input virtual device json config file
        load - Loads the given JSON configuration file and launches devices based on the options provided

        login - Acquire credentials

        reset - Used to stop devices, optionally clean up instance files, and shut down the deprecated cvd server process

        version - Prints version of cvd client and cvd server
```

Output with a running device:
=============================
```
Cuttlefish Virtual Device (CVD) CLI.

usage: cvd <selector/driver options> <command> <args>

Driver Options:
  -help                  Print this message
  -verbosity=<LEVEL>     Adjust Cvd verbosity level. LEVEL is Android log
                         severity. (Required: cvd >= v1.3)

Commands (cvd help <command> for more information):

        cache - Manage the files cached by cvd

        create - Create a Cuttlefish virtual device or environment

        fetch, fetch_cvd - Retrieve build artifacts based on branch and target names

        help - Used to display help information for other commands

        lint - error checks the input virtual device json config file

        load - Loads the given JSON configuration file and launches devices based on the options provided

        login - Acquire credentials

        reset - Used to stop devices, optionally clean up instance files, and shut down the deprecated cvd server process

        version - Prints version of cvd client and cvd server

Selector Options:
  -group_name <name>     Specify the name of the instance group created
                         or selected.
  -instance_name <name>  Selects the device of the given name to perform the
                         commands for.
  -instance_name <names> Takes the names of the devices to create within an
                         instance group. The 'names' is comma-separated.

Device-Specific Commands (cvd help <command> for more information):
        display - Enables hotplug/unplug of displays from running cuttlefish virtual devices

        env - Enumerate + Query APIs for all gRPC services made available by this virtual device instance

        fleet - lists active devices with relevant information

        clear - Clears the instance database, stopping any running instances first.

        bugreport, host_bugreport, cvd_host_bugreport - Run cvd bugreport --help for command description

        stop, stop_cvd - Stop all instances in a group

        powerbtn - Trigger power button event on the device

        powerwash - Reset device to first boot state

        restart - Restart device

        remove, rm - Remove devices and artifacts from the system.

        screen_recording - Record screen contents

        suspend, resume, snapshot_take - Suspend/resume the cuttlefish device, or take snapshot of the device

        start, launch_cvd - Start a Cuttlefish virtual device or environment

        status, cvd_status - Query status of a single instance group.  Use `cvd fleet` for all devices
```

Assisted-by: Gemini:Next
Bug: b/504758273

Author: Databean

base/cvd/cuttlefish/host/commands/cvd/cli/BUILD.bazel

@@ -57,15 +57,13 @@ cf_cc_library(
     srcs = [
         "command_sequence.cpp",
         "request_context.cpp",
-        "//cuttlefish/host/commands/cvd/cli/commands:cmd_list.cpp",
         "//cuttlefish/host/commands/cvd/cli/commands:create.cpp",
         "//cuttlefish/host/commands/cvd/cli/commands:help.cpp",
         "//cuttlefish/host/commands/cvd/cli/commands:load_configs.cpp",
     ],
     hdrs = [
         "command_sequence.h",
         "request_context.h",
-        "//cuttlefish/host/commands/cvd/cli/commands:cmd_list.h",
         "//cuttlefish/host/commands/cvd/cli/commands:create.h",
         "//cuttlefish/host/commands/cvd/cli/commands:help.h",
         "//cuttlefish/host/commands/cvd/cli/commands:load_configs.h",
@@ -91,7 +89,6 @@ cf_cc_library(
         "//cuttlefish/host/commands/cvd/cli/commands:host_tool_target",
         "//cuttlefish/host/commands/cvd/cli/commands:lint",
         "//cuttlefish/host/commands/cvd/cli/commands:login",
-        "//cuttlefish/host/commands/cvd/cli/commands:noop",
         "//cuttlefish/host/commands/cvd/cli/commands:power_btn",
         "//cuttlefish/host/commands/cvd/cli/commands:powerwash",
         "//cuttlefish/host/commands/cvd/cli/commands:remove",

base/cvd/cuttlefish/host/commands/cvd/cli/commands/BUILD.bazel

@@ -6,8 +6,6 @@ package(
 
 exports_files([
     ".clang-tidy",
-    "cmd_list.cpp",
-    "cmd_list.h",
     "create.cpp",
     "create.h",
     "help.cpp",
@@ -218,19 +216,6 @@ cf_cc_library(
     ],
 )
 
-cf_cc_library(
-    name = "noop",
-    srcs = ["noop.cpp"],
-    hdrs = ["noop.h"],
-    deps = [
-        "//cuttlefish/host/commands/cvd/cli:command_request",
-        "//cuttlefish/host/commands/cvd/cli:types",
-        "//cuttlefish/host/commands/cvd/cli/commands:command_handler",
-        "//cuttlefish/result",
-        "@fmt",
-    ],
-)
-
 cf_cc_library(
     name = "power_btn",
     srcs = ["power_btn.cpp"],

base/cvd/cuttlefish/host/commands/cvd/cli/commands/bugreport.cpp

@@ -98,6 +98,7 @@ class CvdBugreportCommandHandler : public CvdCommandHandler {
   cvd_common::Args CmdList() const override;
   Result<std::string> SummaryHelp() const override;
   bool ShouldInterceptHelp() const override;
+  bool RequiresDeviceExists() const override;
   Result<std::string> DetailedHelp(std::vector<std::string>&) const override;
 
  private:
@@ -187,6 +188,7 @@ Result<std::string> CvdBugreportCommandHandler::SummaryHelp() const {
 }
 
 bool CvdBugreportCommandHandler::ShouldInterceptHelp() const { return false; }
+bool CvdBugreportCommandHandler::RequiresDeviceExists() const { return true; }
 
 Result<std::string> CvdBugreportCommandHandler::DetailedHelp(
     std::vector<std::string>& arguments) const {

base/cvd/cuttlefish/host/commands/cvd/cli/commands/clear.cpp

@@ -41,6 +41,7 @@ class CvdClearCommandHandler : public CvdCommandHandler {
   cvd_common::Args CmdList() const override { return {kClearCmd}; }
   Result<std::string> SummaryHelp() const override { return kSummaryHelpText; }
   bool ShouldInterceptHelp() const override { return true; }
+  bool RequiresDeviceExists() const override { return true; }
   Result<std::string> DetailedHelp(std::vector<std::string>&) const override;
 
  private:

base/cvd/cuttlefish/host/commands/cvd/cli/commands/cmd_list.cpp

@@ -26,4 +26,6 @@ Result<bool> CvdCommandHandler::CanHandle(const CommandRequest& request) const {
   return Contains(CmdList(), request.Subcommand());
 }
 
+bool CvdCommandHandler::RequiresDeviceExists() const { return false; }
+
 }  // namespace cuttlefish

base/cvd/cuttlefish/host/commands/cvd/cli/commands/cmd_list.h

@@ -35,6 +35,7 @@ class CvdCommandHandler {
   virtual cvd_common::Args CmdList() const = 0;
   // used for command help text
   virtual Result<std::string> SummaryHelp() const = 0;
+  virtual bool RequiresDeviceExists() const;
   virtual bool ShouldInterceptHelp() const = 0;
   virtual Result<std::string> DetailedHelp(std::vector<std::string>&) const = 0;
 };

base/cvd/cuttlefish/host/commands/cvd/cli/commands/command_handler.cpp

@@ -91,6 +91,8 @@ class CvdDisplayCommandHandler : public CvdCommandHandler {
 
   bool ShouldInterceptHelp() const override { return true; }
 
+  bool RequiresDeviceExists() const override { return true; }
+
   Result<std::string> DetailedHelp(std::vector<std::string>&) const override {
     return kDetailedHelpText;
   }

base/cvd/cuttlefish/host/commands/cvd/cli/commands/command_handler.h

@@ -89,6 +89,8 @@ class CvdEnvCommandHandler : public CvdCommandHandler {
 
   bool ShouldInterceptHelp() const override { return true; }
 
+  bool RequiresDeviceExists() const override { return true; }
+
   Result<std::string> DetailedHelp(std::vector<std::string>&) const override {
     return kDetailedHelpText;
   }