parity(2): insert-mode list bindings (<C-D>/<C-T>/<C-L><C-?>)

Match upstream vimwiki's insert-mode list editing:
  <C-D>      list_change_level(-1)   dedent current item
  <C-T>      list_change_level(+1)   indent current item
  <C-L><C-J> list_cycle_symbol(+1)   cycle marker forward
  <C-L><C-K> list_cycle_symbol(-1)   cycle marker backward
  <C-L><C-M> list_toggle_or_add_chk  toggle if has checkbox, else add `[ ]`

Cycle order matches vimwiki's canonical run:
  - → * → # → 1. → 1) → a) → A) → i) → I) → (wrap)

Both Lua and VimL paths wired. Lua callbacks fire directly (no `<C-o>`
dance) since list_change_level / changeSymbol mutate the buffer via
the LSP applyEdit pipeline, which works cleanly in insert mode. VimL
keeps the `<C-o>:call …<CR>` idiom since that's the standard there.

Harness adds 5 cases covering the new insert-mode bindings plus one
direct LSP roundtrip for changeSymbol — surfaced a long-standing
stale-binary footgun in test-keymaps.sh (rebuilt only when bin was
missing; now rebuilds every run since incremental cargo is fast).
Harness also captures server log_messages and dumps them on failure
so future swallowed-error bugs (Err → log + Ok(None)) are visible.

Gates: 421 Rust / 25 Neovim / 12 Vim.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

scripts/test-keymaps.lua

@@ -101,6 +101,16 @@ local function wait_for_lsp(timeout_ms)
   return nil
 end
 
+-- ===== Capture server log_message events =====
+local server_log = {}
+local orig_handler = vim.lsp.handlers['window/logMessage']
+vim.lsp.handlers['window/logMessage'] = function(err, result, ctx, cfg)
+  if result and result.message then
+    table.insert(server_log, '[' .. tostring(result.type) .. '] ' .. result.message)
+  end
+  if orig_handler then return orig_handler(err, result, ctx, cfg) end
+end
+
 -- ===== Smoke: LSP attached =====
 
 vim.defer_fn(function()
@@ -272,6 +282,58 @@ vim.defer_fn(function()
     wait_ms = 100,
   })
 
+  -- ===== Insert-mode list bindings (Cluster 2) =====
+
+  run('insert.C-L_C-M_adds_checkbox', {
+    lines = { '- task' },
+    cursor = { 1, 0 },
+    keys = 'A<C-L><C-M><Esc>',
+    expect_line = '- [ ] task',
+    expect_at = 1,
+    wait_ms = 200,
+  })
+  run('insert.C-L_C-M_toggles_existing_checkbox', {
+    lines = { '- [ ] task' },
+    cursor = { 1, 0 },
+    keys = 'A<C-L><C-M><Esc>',
+    expect_line = '- [X] task',
+    expect_at = 1,
+  })
+  -- End-to-end regression for changeSymbol over LSP — direct call
+  -- (no keymap) so we can spot a stale `bin/nuwiki-ls` or a dispatch
+  -- error fast. Toggle has separate coverage above via `<C-Space>`.
+  do
+    local ok, err = pcall(function()
+      set_buf({ '- [ ] item', '- [ ] two' })
+      sleep(200)
+      vim.api.nvim_win_set_cursor(0, { 1, 0 })
+      require('nuwiki.commands').list_change_symbol('*', false)
+      sleep(1500)
+      local got = get_line(1)
+      if got ~= '* [ ] item' then
+        error(string.format('change_symbol failed: got %q', got))
+      end
+    end)
+    record(ok, 'direct.list_change_symbol_via_lsp', ok and '' or tostring(err))
+  end
+  run('insert.C-L_C-J_cycles_marker_forward', {
+    lines = { '- item' },
+    cursor = { 1, 0 },
+    keys = 'A<C-L><C-J><Esc>',
+    expect_line = '* item',
+    expect_at = 1,
+    wait_ms = 1500,
+  })
+  run('insert.C-L_C-K_cycles_marker_backward', {
+    -- From `-` going backward wraps to the end of the order (`I)`).
+    lines = { '- item' },
+    cursor = { 1, 0 },
+    keys = 'A<C-L><C-K><Esc>',
+    expect_line = 'I) item',
+    expect_at = 1,
+    wait_ms = 1500,
+  })
+
   -- ===== Diary nav =====
   -- Tested via the LSP open-* responses; can't fully validate without
   -- a populated diary, but at least confirm the maps fire without
@@ -280,6 +342,15 @@ vim.defer_fn(function()
   -- ===== Wrap up =====
 
   table.insert(out_lines, '')
+  -- Dump captured server log_messages only on failure — useful for
+  -- diagnosing dispatch errors that the LSP swallows into log_message.
+  if fail > 0 and #server_log > 0 then
+    table.insert(out_lines, '--- server log_messages ---')
+    for _, l in ipairs(server_log) do
+      table.insert(out_lines, l)
+    end
+    table.insert(out_lines, '')
+  end
   table.insert(out_lines, string.format('SUMMARY: %d passed, %d failed', pass, fail))
   vim.fn.writefile(out_lines, OUT)
   vim.cmd(fail == 0 and 'qall!' or 'cquit!')