add LIKE substring fallback to search and update plan statuses

FTS5 prefix matching misses mid-word substrings (e.g. "ebook" in
"notebook"). When FTS5 returns zero results, fall back to LIKE
query on title and category with proper wildcard escaping. 4 new
tests, 757 total.

Also marks completed plan files (search, admin-redesign,
setup-wizard, products-context) with correct status.

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

docs/plans/admin-redesign.md

@@ -1,6 +1,6 @@
 # Plan: Admin area redesign
 
-Status: Pending
+Status: Complete
 
 ## Overview
 

docs/plans/products-context.md

@@ -1,6 +1,6 @@
 # Plan: Products Context with Provider Integration
 
-> **Status:** Phase 1 Complete (c5c06d9) - See [PROGRESS.md](../../PROGRESS.md) for current status.
+> **Status:** Complete (c5c06d9, 037cd16, 57c3ba0) - See [PROGRESS.md](../../PROGRESS.md) for current status.
 
 ## Goal
 Build a Products context that syncs products from external POD providers (Printify first), stores them locally, and enables order submission for fulfillment.

docs/plans/search.md

@@ -1,6 +1,6 @@
 # Plan: Implement product search in search modal
 
-Status: Pending (after usability fixes)
+Status: Complete (037cd16, 57c3ba0)
 
 ## Overview
 

docs/plans/setup-wizard.md

@@ -1,6 +1,6 @@
 # Plan: Setup wizard and "go live" gate
 
-Status: Pending
+Status: Complete
 
 ## Overview