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>/

algo/skills/document-improvement/reference.md

@@ -0,0 +1,82 @@
+# Document Improvement — Reference Checklist
+
+Condensed rules for correcting scientific and technical documents. Source: project writing guide.
+
+## Titles
+
+| Incorrect | Correct |
+|-----------|---------|
+| ## Introduction | ## Introduction de [objet/section] |
+| ## Conclusion | ## Conclusion de [objet/section] |
+
+All Introduction and Conclusion titles must be at level `##`.
+
+## Neutrality (strict)
+
+**Remove or rewrite:**
+- Auto-appreciation: "important", "majeur", "robuste", "rigoureux", "ambitieux"
+- Editorial justification: "volontairement", "conservateur", "verrou", "discipline"
+- Reader address: "le lecteur verra que…" → factual statement
+- Introspection: "nous avons choisi…" → neutral formulation
+- Meta-commentary on the text itself
+
+**Use instead:**
+- Factual: "On définit…", "On suppose…", "On montre…", "Il s'ensuit…"
+- Structural references: "voir Chapitre X", "d'après la Proposition Y" (without evaluative terms)
+
+## Transitions
+
+- Replace "La continuation ainsi…" by content-driven transitions
+- Each paragraph should follow from the mathematical content, not from meta-phrases
+- Avoid "on poursuit de la même manière" without specifying what follows
+
+## Hypotheses and results
+
+- Before each lemma, proposition, theorem: state hypotheses explicitly
+- In the proof: indicate when each hypothesis is used
+- No implicit or "obvious" hypotheses
+
+## References and citations
+
+- Cite exact source (theorem, page, equation number)
+- Avoid "il est bien connu que" without reference
+- For overlap with literature: state the difference (hypotheses, framework) factually
+
+## Quantifiers and domains
+
+- Explicit quantifiers: "pour tout", "il existe", "il existe un unique" with clear domain
+- Explicit domain of definition for functions and operators
+- Validity conditions in the statement, not only in the proof
+
+## Terminology
+
+- One concept = one term throughout
+- No fluctuating synonyms for the same object
+- For long documents: recall local conventions at section start if needed
+
+## Proofs
+
+- No "il est facile de voir" or "on laisse au lecteur" without a precise pointer
+- Either detail the argument or refer to a lemma/reference
+- Long calculations: state the intermediate result, move details to appendix with reference
+
+## Conjectures and open questions
+
+- Neutral formulation: "On conjecture que…", "Il serait naturel de se demander si…"
+- No overstatement of importance
+- Limits of the framework: recall restrictive hypotheses in section conclusion if relevant
+
+## Voice and tense
+
+- Present atemporal for mathematical statements
+- Uniform voice: either "on" or passive throughout
+- Future only for explicit forward references ("on verra en 4.2 que…")
+
+## Quick scan patterns
+
+When scanning a chunk, flag:
+- `## Introduction` or `## Conclusion` without "de …"
+- "important", "majeur", "volontairement", "verrou", "discipline"
+- "Le lecteur", "on laisse au lecteur", "il est facile de voir"
+- "La continuation ainsi", "on poursuit de la même manière"
+- "il est bien connu que" without citation