feat: add Google engine using GSA User-Agent scraping

SearXNG approach: use Google Search Appliance (GSA) User-Agent
pool — these are whitelisted enterprise identifiers Google trusts.

Key techniques:
- GSA User-Agent (iPhone OS + GSA/ version) instead of Chrome desktop
- CONSENT=YES+ cookie to bypass EU consent wall
- Parse /url?q= redirector URLs (unquote + strip &sa= params)
- div.MjjYud class for result containers (SearXNG selector)
- data-sncf divs for snippets
- detect sorry.google.com blocks
- Suggestions from ouy7Mc class cards

internal/engines/planner.go

@@ -91,6 +91,7 @@ func inferFromCategories(categories []string) []string {
 			set["qwant"] = true
 			set["duckduckgo"] = true
 			set["bing"] = true
+			set["google"] = true
 		case "science", "scientific publications":
 			set["arxiv"] = true
 			set["crossref"] = true
@@ -106,7 +107,7 @@ func inferFromCategories(categories []string) []string {
 		out = append(out, e)
 	}
 	// stable order
-	order := map[string]int{"wikipedia": 0, "braveapi": 1, "qwant": 2, "duckduckgo": 3, "bing": 4, "arxiv": 5, "crossref": 6, "github": 7, "reddit": 8}
+	order := map[string]int{"wikipedia": 0, "braveapi": 1, "qwant": 2, "duckduckgo": 3, "bing": 4, "google": 5, "arxiv": 6, "crossref": 7, "github": 8, "reddit": 9}
 	sortByOrder(out, order)
 	return out
 }