fix(forge): autocompletion Tab naturelle et fiable (BUG-055)

backend/ai.py

@@ -353,10 +353,13 @@ async def ai_generate_frontmatter(text: str, provider: ProviderName | None = Non
 
 
 async def ai_inline_complete(text: str, provider: ProviderName | None = None) -> str:
-    """Inline completion — suggest continuation."""
+    """Inline completion — suggest a short continuation of the text before the cursor."""
     return await _call_deepseek_openrouter(
-        f"Complete this text naturally. Return only the completion (just the new text, no repetition):\n\n{text}",
-        SYSTEM_PROMPT, provider, temperature=0.3, max_tokens=512,
+        "Continue the text below in the same language. Reply with ONLY the "
+        "continuation: no repetition, no quotes, no explanation, at most one "
+        "short sentence. If the text ends with a partial word, finish that word.\n\n"
+        + text,
+        SYSTEM_PROMPT, provider, temperature=0.2, max_tokens=128,
     )