feat: add EN/ES/RO language selector for AI pitch generation

- db.py: add `language` column to ai_queue; migration; queue_ai() accepts
  language param and re-queues with ON CONFLICT UPDATE so changing language works
- main.py: batch and single assess endpoints accept `language` from request body
- enricher.py: ai_worker_loop reads language column, passes to _assess_one()
- replicate_ai.py: assess_domain() and _build_prompt() accept language param;
  OUTPUT LANGUAGE section injected into prompt so Gemini writes pitch/email in
  the requested language (EN/ES/RO)
- index.html: flag dropdown (🇪🇸/🇬🇧/🇷🇴) next to AI Assess button; aiLang
  state default ES; language sent in all batch assessment requests

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/main.py

@@ -173,7 +173,10 @@ async def ai_assess_batch(body: dict):
     domains_list = body.get("domains", [])
     if not domains_list:
         return JSONResponse({"error": "no domains provided"}, status_code=400)
-    await queue_ai(domains_list)
+    language = body.get("language", "ES").upper()
+    if language not in ("EN", "ES", "RO"):
+        language = "ES"
+    await queue_ai(domains_list, language=language)
     ensure_workers_alive()   # ensure AI worker is alive when jobs are queued
     return {"queued": len(domains_list)}
 
@@ -233,10 +236,13 @@ async def ai_assess_single(body: dict):
     domain = body.get("domain")
     if not domain:
         return JSONResponse({"error": "no domain"}, status_code=400)
+    language = body.get("language", "ES").upper()
+    if language not in ("EN", "ES", "RO"):
+        language = "ES"
     from app.site_analyzer import analyze_site
     from app.replicate_ai import assess_domain as gemini_assess
     analysis = await analyze_site(domain)
-    assessment = await gemini_assess(analysis)
+    assessment = await gemini_assess(analysis, language=language)
     await save_ai_assessment(domain, assessment, site_analysis=analysis)
     return {**assessment, "site_analysis": analysis}