Remove test_plan gate from the codebase

The test_plan field was a gate from the old interactive web UI workflow
where a human would approve a test plan before the LLM could write code.
With autonomous coder agents, this gate is dead weight — coders sometimes
obey the README's "wait for approval" instruction and produce no code.

Removes: TestPlanStatus enum, ensure_test_plan_approved checks in fs/shell,
set_test_plan MCP tool + handler, test_plan from story/bug front matter
creation, test_plan validation in validate_story_dirs, and all related tests.
Updates README to remove Step 2 (Test Planning) and renumber steps.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/io/shell.rs

@@ -1,7 +1,5 @@
-use crate::io::story_metadata::{TestPlanStatus, parse_front_matter};
 use crate::state::SessionState;
 use serde::Serialize;
-use std::fs;
 use std::path::PathBuf;
 use std::process::Command;
 
@@ -10,30 +8,6 @@ fn get_project_root(state: &SessionState) -> Result<PathBuf, String> {
     state.get_project_root()
 }
 
-async fn ensure_test_plan_approved(root: PathBuf) -> Result<(), String> {
-    let approved = tokio::task::spawn_blocking(move || {
-        let story_path = root
-            .join(".story_kit")
-            .join("stories")
-            .join("current")
-            .join("26_establish_tdd_workflow_and_gates.md");
-        let contents = fs::read_to_string(&story_path)
-            .map_err(|e| format!("Failed to read story file for test plan approval: {e}"))?;
-        let metadata = parse_front_matter(&contents)
-            .map_err(|e| format!("Failed to parse story front matter: {e:?}"))?;
-
-        Ok::<bool, String>(matches!(metadata.test_plan, Some(TestPlanStatus::Approved)))
-    })
-    .await
-    .map_err(|e| format!("Task failed: {e}"))??;
-
-    if approved {
-        Ok(())
-    } else {
-        Err("Test plan is not approved for the current story.".to_string())
-    }
-}
-
 #[derive(Serialize, Debug, poem_openapi::Object)]
 pub struct CommandOutput {
     pub stdout: String,
@@ -80,7 +54,6 @@ pub async fn exec_shell(
     state: &SessionState,
 ) -> Result<CommandOutput, String> {
     let root = get_project_root(state)?;
-    ensure_test_plan_approved(root.clone()).await?;
     exec_shell_impl(command, args, root).await
 }
 
@@ -89,24 +62,6 @@ mod tests {
     use super::*;
     use tempfile::tempdir;
 
-    #[tokio::test]
-    async fn exec_shell_requires_approved_test_plan() {
-        let dir = tempdir().expect("tempdir");
-        let state = SessionState::default();
-
-        {
-            let mut root = state.project_root.lock().expect("lock project root");
-            *root = Some(dir.path().to_path_buf());
-        }
-
-        let result = exec_shell("ls".to_string(), Vec::new(), &state).await;
-
-        assert!(
-            result.is_err(),
-            "expected shell execution to be blocked when test plan is not approved"
-        );
-    }
-
     #[tokio::test]
     async fn exec_shell_impl_rejects_disallowed_command() {
         let dir = tempdir().unwrap();