test(keymaps): headless Neovim harness for buffer-local bindings + CI

`scripts/test-keymaps.sh` boots `nvim --headless` against a scratch
wiki, sources `scripts/test-keymaps.lua`, and asserts the post-state
of each buffer-local mapping registered by `ftplugin/vimwiki.vim` +
`lua/nuwiki/keymaps.lua`.

The harness covers the bindings that actually have observable effects
on the buffer or cursor:

- **Lists** (LSP round-trip): `<C-Space>` / `<C-@>` / `<Nul>` toggle,
  `gln` cycle, `glx` reject, plus a `[X]→[ ]` round-trip.
- **Tasks**: `gnt` jumps to the next unfinished `[ ]`.
- **Headings** (LSP round-trip): `=` adds a level, `-` removes one,
  `=` on h6 clamps without growing.
- **Header nav** (pure Lua): `]]` next, `[[` prev, `]u` parent.
- **Link nav** (pure Lua): `<Tab>` to the next `[[…]]`.
- **`<CR>` two-step**: first press wraps a bare word as `[[word]]`
  and stops (matches vimwiki's review-then-follow).
- **Bullet continuation**: `o` / `O` keep the marker, and `o` on a
  `[ ]` line carries the checkbox forward.

Each case sets buffer lines, places the cursor (1-based), fires
`nvim_feedkeys` with `replace_termcodes`, waits long enough for the
LSP `executeCommand` round-trip (800 ms by default; 100 ms for the
pure-client maps), and asserts either the resulting lines, a specific
line, the cursor's new line, or the buffer's new name.

Output goes via `$NUWIKI_KEYMAP_RESULTS` (env-var IPC keeps it
robust to `--clean -u` argument parsing). Exit code mirrors the
harness: 0 on green, 1 on any FAIL. Local run yields:

  SUMMARY: 19 passed, 0 failed

CI: new `keymaps` job in `.gitea/workflows/ci.yaml` installs Neovim
and runs the script, so a regression in `lua/nuwiki/keymaps.lua`,
`autoload/nuwiki/commands.vim`, or the LSP command surface is caught
on every push.

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

scripts/test-keymaps.sh

@@ -0,0 +1,66 @@
+#!/usr/bin/env bash
+#
+# scripts/test-keymaps.sh — drive scripts/test-keymaps.lua under
+# headless Neovim and report pass/fail per buffer-local keymap.
+#
+# The Lua harness needs a real LSP attachment (most keymaps dispatch
+# `workspace/executeCommand`), so we:
+#   1. ensure `bin/nuwiki-ls` is built (release),
+#   2. spin up a scratch wiki under a temp dir,
+#   3. invoke `nvim --headless` with a minimal init that loads the
+#      plugin + calls `setup()`, then sources the harness Lua.
+#
+# Exit code mirrors the harness: 0 on green, 1 on any failure.
+
+set -euo pipefail
+
+REPO_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+TMP="$(mktemp -d -t nuwiki-keymap-test-XXXXXX)"
+trap 'rm -rf "$TMP"' EXIT
+
+log() { printf '\033[1;34m[keymap-test]\033[0m %s\n' "$*"; }
+
+# Build the LSP binary if missing.
+BIN="$REPO_ROOT/bin/nuwiki-ls"
+if [[ ! -x "$BIN" ]]; then
+  log 'building nuwiki-ls (release)…'
+  cargo build --release -p nuwiki-ls --manifest-path "$REPO_ROOT/Cargo.toml" >/dev/null
+  mkdir -p "$REPO_ROOT/bin"
+  ln -sf "$REPO_ROOT/target/release/nuwiki-ls" "$BIN"
+fi
+
+mkdir -p "$TMP/wiki"
+echo "= seed =" > "$TMP/wiki/index.wiki"
+
+INIT="$TMP/init.lua"
+cat > "$INIT" <<EOF
+-- Keep the harness self-contained; no plugin manager required.
+vim.opt.runtimepath:prepend('$REPO_ROOT')
+vim.g.nuwiki_binary_path = '$BIN'
+require('nuwiki').setup({ wiki_root = '$TMP/wiki' })
+EOF
+
+RESULTS="$TMP/results.txt"
+log "running harness…"
+
+# `nvim --headless -u init.lua FILE +luafile …` — the harness's
+# `vim.defer_fn` lets the LSP attach before tests fire, then writes
+# the results file and exits. Output path is plumbed through env.
+NUWIKI_KEYMAP_RESULTS="$RESULTS" \
+  nvim --clean -u "$INIT" --headless "$TMP/wiki/index.wiki" \
+    -c "luafile $REPO_ROOT/scripts/test-keymaps.lua" \
+    >"$TMP/nvim.log" 2>&1 || true
+
+if [[ ! -f "$RESULTS" ]]; then
+  echo 'keymap test harness produced no output' >&2
+  echo '--- nvim log ---' >&2
+  cat "$TMP/nvim.log" >&2 || true
+  exit 1
+fi
+
+cat "$RESULTS"
+
+if grep -qE '^SUMMARY: [0-9]+ passed, 0 failed' "$RESULTS"; then
+  exit 0
+fi
+exit 1