refactor(cli): rename plan lifecycle-list and lifecycle-apply to match specification

Renames `plan lifecycle-list` to `plan list` and `plan lifecycle-apply` to `plan apply` to align with the specification's canonical command names. Removes legacy V2 plan commands that occupied those names.

- Renamed CLI command registrations from lifecycle-list/lifecycle-apply to list/apply
- Removed legacy V2 apply and list commands (~200 lines)
- Updated apply shortcut in main.py to delegate to v3 lifecycle
- Added defensive null check for plan existence in apply command
- Updated 63+ test, doc, and benchmark files for consistency

Closes #881

Co-authored-by: Jeffrey Phillips Freeman <the@jeffreyfreeman.me>
Co-committed-by: Jeffrey Phillips Freeman <the@jeffreyfreeman.me>

docs/reference/plan_cli.md

@@ -7,10 +7,10 @@ The `agents plan` command group manages plans in the CleverAgents v3 plan lifecy
 | Command                        | Description                             |
 |--------------------------------|-----------------------------------------|
 | `agents plan use`              | Create plan from action + project(s)    |
-| `agents plan lifecycle-list`   | List plans with optional filters        |
+| `agents plan list`             | List plans with optional filters        |
 | `agents plan status`           | Show plan status / details              |
 | `agents plan execute`          | Run Strategize + Execute (auto-apply if profile permits) |
-| `agents plan lifecycle-apply`  | Transition to Apply and complete it     |
+| `agents plan apply`            | Transition to Apply and complete it     |
 | `agents plan cancel`           | Cancel a non-terminal plan              |
 | `agents plan diff`             | Show ChangeSet as unified diff          |
 | `agents plan artifacts`        | Show ChangeSet ID, sandbox refs, summary|
@@ -95,14 +95,14 @@ plans including automation profile and invariant count columns.
 - **Invariants**: Count of attached invariants
 - **Terminal**: Whether the plan is in a terminal state
 
-## `agents plan lifecycle-list`
+## `agents plan list`
 
 List v3 lifecycle plans with optional filtering.
 
 ### Synopsis
 
 ```bash
-agents plan lifecycle-list [REGEX] [OPTIONS]
+agents plan list [REGEX] [OPTIONS]
 ```
 
 ### Options
@@ -151,7 +151,7 @@ reads after phase transitions.  See
 [CLI Executor Wiring](plan_execute.md#cli-executor-wiring-_get_plan_executor)
 for details.
 
-## `agents plan lifecycle-apply`
+## `agents plan apply`
 
 Transition a plan to Apply phase and complete it. Because Apply is a
 destructive operation (it merges sandbox changesets into real project
@@ -166,7 +166,7 @@ completes the apply processing, driving the plan to the terminal
 ### Synopsis
 
 ```bash
-agents plan lifecycle-apply [--yes|-y] [PLAN_ID] [--format FORMAT]
+agents plan apply [--yes|-y] [PLAN_ID] [--format FORMAT]
 ```
 
 ### Options

docs/reference/read_only_actions.md

@@ -10,7 +10,7 @@ A **read-only plan** is created when the originating Action has
 `read_only=True`.  The flag propagates through the execution layers:
 
 ```
-Plan.read_only  ->  CLI fail-fast guard (plan execute / plan lifecycle-apply)
+Plan.read_only  ->  CLI fail-fast guard (plan execute / plan apply)
                 ->  ExecuteStubActor.execute(read_only=...) -> ChangeSetCapture
                 ->  ToolRuntime._enforce_capabilities (via ToolExecutionContext)
                 ->  SkillContext.enforce_write_guard
@@ -79,7 +79,7 @@ reads `plan.read_only` from the plan model.
 
 Location: `src/cleveragents/cli/commands/plan.py`
 
-Both `plan execute` and `plan lifecycle-apply` check `plan.read_only`
+Both `plan execute` and `plan apply` check `plan.read_only`
 before calling the lifecycle service.  If the plan is read-only, the
 CLI prints an error and aborts without making any state transitions.