Initial: desk + ncantu placeholder + per-project cursor configs

**Motivations:**
- Centraliser les fichiers Cursor (rules, skills, agents, commands, hooks) par user et par projet

**Root causes:**
- N/A

**Correctifs:**
- N/A

**Evolutions:**
- desk: rules, skills-cursor, agents, commands, hooks, argv/hooks/mcp.json
- ncantu: README placeholder
- 4NK_node, algo, builazoo, ia_local, lecoffre_ng, lecoffre_ng_pprod, lecoffre_ng_test: .cursor contents

**Pages affectées:**
- cursor/desk/, cursor/ncantu/, cursor/<project>/

desk/hooks/lib.sh

@@ -0,0 +1,31 @@
+#!/bin/bash
+# Shared helpers for Cursor hooks. Source with: source "$(dirname "$0")/lib.sh"
+
+LOG_DIR="${CURSOR_HOOKS_LOG_DIR:-$HOME/.cursor/logs}"
+LOG_FILE="${LOG_DIR}/hooks.log"
+
+log_event() {
+  local event="$1"
+  local summary="$2"
+  mkdir -p "$LOG_DIR"
+  echo "[$(date -Iseconds)] [$event] $summary" >> "$LOG_FILE"
+}
+
+log_json() {
+  local event="$1"
+  local json="$2"
+  mkdir -p "$LOG_DIR"
+  echo "[$(date -Iseconds)] [$event] $json" >> "$LOG_FILE"
+}
+
+log_json_truncated() {
+  local event="$1"
+  local json="$2"
+  local max="${3:-500}"
+  mkdir -p "$LOG_DIR"
+  if [ ${#json} -gt "$max" ]; then
+    echo "[$(date -Iseconds)] [$event] ${json:0:$max}... (truncated)" >> "$LOG_FILE"
+  else
+    echo "[$(date -Iseconds)] [$event] $json" >> "$LOG_FILE"
+  fi
+}