Add enhanced search and filtering (M2 feature)

- Add /api/v1/tags endpoint for listing available tags
- Enhance search API with tag filtering (AND logic), multi-category
  filtering (OR logic), owner filter, download range, and date range
- Add faceted response support (category/tag/owner counts)
- Update registry client with new search parameters and get_tags method
- Add CLI search options: -t/--tag, -o/--owner, --min-downloads,
  --popular, --new, --since, --before, --json, --show-facets
- Add new 'registry tags' CLI subcommand
- Add web UI filter sidebar with checkboxes, dropdowns, and active
  filter chips with URL-based state management
- Display clickable tags on tool cards

Co-Authored-By: Claude Opus 4.5 <[email protected]>

src/cmdforge/cli/registry_commands.py

@@ -1,5 +1,6 @@
 """Registry commands."""
 
+import json
 import sys
 from pathlib import Path
 
@@ -15,6 +16,8 @@ def cmd_registry(args):
 
     if args.registry_cmd == "search":
         return _cmd_registry_search(args)
+    elif args.registry_cmd == "tags":
+        return _cmd_registry_tags(args)
     elif args.registry_cmd == "install":
         return _cmd_registry_install(args)
     elif args.registry_cmd == "uninstall":
@@ -33,6 +36,7 @@ def cmd_registry(args):
         # Default: show registry help
         print("Registry commands:")
         print("  search <query>     Search for tools")
+        print("  tags               List available tags")
         print("  install <tool>     Install a tool")
         print("  uninstall <tool>   Uninstall a tool")
         print("  info <tool>        Show tool information")
@@ -49,27 +53,73 @@ def _cmd_registry_search(args):
 
     try:
         client = get_client()
+
+        # Handle shortcut flags
+        min_downloads = getattr(args, 'min_downloads', None)
+        max_downloads = None
+        if getattr(args, 'popular', False):
+            min_downloads = 100
+        if getattr(args, 'new', False):
+            max_downloads = 10
+
         results = client.search_tools(
             query=args.query,
-            category=args.category,
-            per_page=args.limit or 20
+            category=getattr(args, 'category', None),
+            tags=getattr(args, 'tags', None),
+            owner=getattr(args, 'owner', None),
+            min_downloads=min_downloads,
+            max_downloads=max_downloads,
+            published_after=getattr(args, 'since', None),
+            published_before=getattr(args, 'before', None),
+            include_deprecated=getattr(args, 'deprecated', False),
+            include_facets=getattr(args, 'show_facets', False),
+            per_page=args.limit or 20,
+            sort=getattr(args, 'sort', 'relevance')
         )
 
+        # JSON output
+        if getattr(args, 'json', False):
+            output = {
+                "query": args.query,
+                "total": results.total,
+                "results": results.data
+            }
+            if results.facets:
+                output["facets"] = results.facets
+            print(json.dumps(output, indent=2))
+            return 0
+
         if not results.data:
             print(f"No tools found matching '{args.query}'")
             return 0
 
-        print(f"Found {results.total} tools:\n")
+        print(f"Found {results.total} tools matching \"{args.query}\":")
+
+        # Show facets summary if requested
+        if results.facets:
+            cats = results.facets.get("categories", [])[:5]
+            tags = results.facets.get("tags", [])[:5]
+            if cats:
+                cat_str = ", ".join(f"{c['name']} ({c['count']})" for c in cats)
+                print(f"\nCategories: {cat_str}")
+            if tags:
+                tag_str = ", ".join(f"{t['name']} ({t['count']})" for t in tags)
+                print(f"Top Tags: {tag_str}")
+
+        print()
         for tool in results.data:
             owner = tool.get("owner", "")
             name = tool.get("name", "")
             version = tool.get("version", "")
             desc = tool.get("description", "")
             downloads = tool.get("downloads", 0)
+            tags = tool.get("tags", [])
 
             print(f"  {owner}/{name} v{version}")
             print(f"    {desc[:60]}{'...' if len(desc) > 60 else ''}")
-            print(f"    Downloads: {downloads}")
+            if tags:
+                print(f"    Tags: {', '.join(tags[:5])}")
+            print(f"    Downloads: {downloads:,}")
             print()
 
         if results.total_pages > 1:
@@ -92,6 +142,43 @@ def _cmd_registry_search(args):
     return 0
 
 
+def _cmd_registry_tags(args):
+    """List available tags."""
+    from ..registry_client import RegistryError, get_client
+
+    try:
+        client = get_client()
+        tags = client.get_tags(
+            category=getattr(args, 'category', None),
+            limit=getattr(args, 'limit', 50)
+        )
+
+        # JSON output
+        if getattr(args, 'json', False):
+            print(json.dumps({"tags": tags}, indent=2))
+            return 0
+
+        if not tags:
+            print("No tags found")
+            return 0
+
+        print(f"Available tags ({len(tags)}):\n")
+        for tag in tags:
+            print(f"  {tag['name']:20} ({tag['count']} tools)")
+
+    except RegistryError as e:
+        if e.code == "CONNECTION_ERROR":
+            print("Could not connect to the registry.", file=sys.stderr)
+        else:
+            print(f"Error: {e.message}", file=sys.stderr)
+        return 1
+    except Exception as e:
+        print(f"Error: {e}", file=sys.stderr)
+        return 1
+
+    return 0
+
+
 def _cmd_registry_install(args):
     """Install a tool from the registry."""
     from ..registry_client import RegistryError