Add sandlot show command to display prompt and diff for a branch

src/cli.ts

@@ -390,6 +390,45 @@ program
     }
   })
 
+// ── sandlot show <branch> ───────────────────────────────────────────
+
+program
+  .command("show")
+  .argument("<branch>", "branch name")
+  .description("Show the prompt and full diff for a branch (for code review)")
+  .action(async (branch: string) => {
+    const root = await git.repoRoot()
+    const session = await state.getSession(root, branch)
+    if (!session) {
+      console.error(`No session found for branch "${branch}".`)
+      process.exit(1)
+    }
+
+    const main = await git.mainBranch(root)
+    const result = await $`git -C ${session.worktree} diff --color=always ${main}...${branch}`.nothrow().quiet()
+    if (result.exitCode !== 0) {
+      console.error("git diff failed")
+      process.exit(1)
+    }
+
+    let output = ""
+    if (session.prompt) {
+      output += `PROMPT: ${session.prompt}\n\n`
+    }
+    output += result.text()
+
+    const lines = output.split("\n").length
+    const termHeight = process.stdout.rows || 24
+    if (lines > termHeight) {
+      const pager = Bun.spawn(["less", "-R"], { stdin: "pipe", stdout: "inherit", stderr: "inherit" })
+      pager.stdin.write(output)
+      pager.stdin.end()
+      await pager.exited
+    } else {
+      process.stdout.write(output)
+    }
+  })
+
 // ── sandlot log <branch> ────────────────────────────────────────────
 
 program