test(replay): fix agent instructions and dump

Author: cameronr

AGENTS.md

@@ -1,6 +1,7 @@
 # AGENTS.md
 
 ## Build, Lint, and Test
+
 - **Run all tests:** `./run_tests.sh`
 - **Minimal tests:**
   `nvim --headless -u tests/minimal/init.lua -c "lua require('plenary.test_harness').test_directory('./tests/minimal', {minimal_init = './tests/minimal/init.lua', sequential = true})"`
@@ -9,12 +10,13 @@
 - **Run a single test:** Replace the directory in the above command with the test file path, e.g.:
   `nvim --headless -u tests/manual/init.lua -c "lua require('plenary.test_harness').test_directory('./tests/unit/job_spec.lua', {minimal_init = './tests/minimal/init.lua'})"`
 - **Manual/Visual tests:** `./tests/manual/run_replay.sh` - Replay captured event data for visual testing
-- **Debug rendering in headless mode:** 
-  `nvim --headless -u tests/manual/init_replay.lua "+ReplayHeadless" "+ReplayLoad tests/data/FILE.json" "+ReplayAll 10"`
+- **Debug rendering in headless mode:**
+  `nvim --headless -u tests/manual/init_replay.lua "+ReplayHeadless" "+ReplayLoad tests/data/FILE.json" "+ReplayAll 1" "+sleep 500m | qa!"`
   This will replay events and dump the output buffer to stdout, useful for debugging rendering issues without a UI.
 - **Lint:** No explicit lint command; follow Lua best practices.
 
 ## Code Style Guidelines
+
 - **Imports:** `local mod = require('mod')` at the top. Group standard, then project imports.
 - **Formatting:** 2 spaces per indent. No trailing whitespace. Lines ≤ 100 chars.
 - **Types:** Use Lua annotations (`---@class`, `---@field`, etc.) for public APIs/config.
@@ -26,4 +28,3 @@
 - **Tests:** Place in `tests/minimal/` or `tests/unit/`. Manual/visual tests in `tests/manual/`.
 
 _Agentic coding agents must follow these conventions strictly for consistency and reliability._
-

tests/manual/renderer_replay.lua

@@ -248,7 +248,7 @@ function M.dump_buffer_and_quit()
     end
 
     local lines = vim.api.nvim_buf_get_lines(buf, 0, -1, false)
-    local extmarks = vim.api.nvim_buf_get_extmarks(buf, renderer._namespace, 0, -1, { details = true })
+    local extmarks = vim.api.nvim_buf_get_extmarks(buf, output_window.namespace, 0, -1, { details = true })
 
     local extmarks_by_line = {}
     for _, mark in ipairs(extmarks) do