Migliorate llm_short_description per tutti i connector — tool names espliciti

Ogni connector.json ora ha una llm_short_description che elenca i tool
specifici che espone, così l'LLM sa esattamente cosa attivare (lazy load).

SKALD.md: documentata criticità del campo llm_short_description
nel system prompt dell'LLM.

connectors/tavily/connector.json

@@ -14,7 +14,7 @@
     {
       "lang": "en",
       "description": "Real-time web search and page extraction via Tavily.",
-      "llm_short_description": "Search the web and extract page content through Tavily."
+      "llm_short_description": "Web search engine: search the web, extract page content, crawl full sites, summarize/aggregate results across multiple queries. Tools: tavily_search (web + news + images), tavily_extract (full page content), tavily_crawl (multi-page crawling), tavily_map (discover URLs on a domain), tavily_research (multi-query research loop). API key required."
     }
   ],
   "auth": {