Fix Claude Code Home Manager config

Generate Claude settings from Nix so managed commands use the correct home directory, add declarative keybindings for Shift+Enter newline support, and replace the broken inline docs hook with a portable script.

Also stop exporting CLAUDE_CONFIG_DIR so Claude no longer splits managed config between ~/.claude and ~/.config/claude, and fix the status line script shebang for NixOS.

Co-authored-by: Codex <noreply@openai.com>

config/claude/sync-docs.sh

@@ -0,0 +1,48 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+docs_dir="${HOME}/Documents/GitHub/claude-code-docs"
+manifest="${docs_dir}/docs/docs_manifest.json"
+last_pull="${docs_dir}/.last_pull"
+
+file_path="$(jq -r '.tool_input.file_path // empty' 2>/dev/null || true)"
+case "${file_path}" in
+  "${docs_dir}"/*) ;;
+  *) exit 0 ;;
+esac
+
+if [[ ! -d "${docs_dir}/.git" || ! -f "${manifest}" ]]; then
+  exit 0
+fi
+
+github_unix="$(
+  python3 - "${manifest}" <<'PY'
+import datetime
+import json
+import sys
+
+manifest_path = sys.argv[1]
+
+try:
+    with open(manifest_path, encoding="utf-8") as handle:
+        last_updated = json.load(handle).get("last_updated", "")
+    last_updated = last_updated.split(".", 1)[0]
+    parsed = datetime.datetime.strptime(last_updated, "%Y-%m-%dT%H:%M:%S")
+    print(int(parsed.replace(tzinfo=datetime.timezone.utc).timestamp()))
+except Exception:
+    print(0)
+PY
+)"
+
+last_synced=0
+if [[ -f "${last_pull}" ]]; then
+  last_synced="$(cat "${last_pull}" 2>/dev/null || echo 0)"
+fi
+
+if [[ "${github_unix}" -le "${last_synced}" ]]; then
+  exit 0
+fi
+
+printf 'Syncing Claude docs to latest version...\n' >&2
+git -C "${docs_dir}" pull --quiet
+date +%s > "${last_pull}"