Add Community Formula Library feature

Companies can now share their custom formula templates to a platform-wide
community library. Other tenants can browse, preview, and import formulas
as independent local copies. Includes attribution (source company name),
"Inspired by" lineage for re-contributed formulas, import counts, own-formula
badge, cascade diagram nullification, and AI assistant + help docs updates.

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

src/PowderCoating.Web/Program.cs

@@ -220,6 +220,7 @@ builder.Services.AddScoped<IAiHelpService, AiHelpService>();
 builder.Services.AddScoped<IAiCatalogPriceCheckService, AiCatalogPriceCheckService>();
 builder.Services.AddScoped<IInventoryAiLookupService, InventoryAiLookupService>();
 builder.Services.AddScoped<ICustomFormulaAiService, CustomFormulaAiService>();
+builder.Services.AddScoped<IFormulaLibraryService, FormulaLibraryService>();
 builder.Services.AddHttpClient();
 builder.Services.AddScoped<ICompanyLogoService, CompanyLogoService>();
 builder.Services.AddScoped<IEquipmentManualService, EquipmentManualService>();
@@ -294,6 +295,7 @@ cfg.AddProfile(new CatalogProfile());
         cfg.AddProfile(new PurchaseOrderProfile());
         cfg.AddProfile(new PricingTierProfile());
         cfg.AddProfile(new CustomItemTemplateProfile());
+        cfg.AddProfile(new FormulaLibraryProfile());
     }, loggerFactory);
     return config.CreateMapper();
 });