Add platform powder catalog management UI with full CRUD and AI lookup

- PowderCatalogController: Create, Edit, ToggleDiscontinued actions; searchable/filterable/sortable Index with pagination; AiLookup and AiAugmentFromUrl endpoints backed by IInventoryAiLookupService
- New views: Create, Edit, _Form partial (with AI-assisted field population), overhauled Index grid with completeness quality badges and responsive mobile cards
- New ViewModels: PowderCatalogIndexViewModel, PowderCatalogFormViewModel, PowderCatalogListItemViewModel
- AI lookup improvements: SpecificGravity field added to InventoryAiLookupResult; ApplyPowderFallbacks derives CoverageSqFtPerLb from specific gravity when docs omit it; DefaultTransferEfficiency (65%) applied everywhere transfer efficiency is null
- powder-catalog-ai-lookup.js: client-side AI lookup and URL augment wiring for the catalog form

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

TODO.txt

@@ -1,5 +1,11 @@
 Shop Management App TO DO List
 ==============================
+-Inventory Lookup not always finding price for Columbia Coatings
+-Logging powder usage and choosing a job doesn't record properly in the activity section of the powder itself
+-Need to allow deleting of powder usage entries, or at least editing in case of a goof up
+-Still random weird characters on a bunch of pages.  Intake button for example on the jobs screen shows: Intake ✓
+                               
+
 -Google review request email after a job
 -Check my ChatGPT chat about surface area for a few solid ideas for the system
 -Fix up approve/decline messages between customer and user on quote approval feature