refactor: Remove dedicated /tools endpoints, use /programs?behavior=tool instead

Eliminates inconsistency where tools had their own filtered view but daemons and frontends didn't.

Changes:
- API: Removed tools router and ToolSummary/ToolDetail models. Added optional behavior query parameter to GET /programs for filtering by program type (tool, daemon, frontend).
- Frontend: Updated hooks to pass behavior param to usePrograms instead of separate useTools. Updated components to use ProgramSummary type. Removed useToolDetail hook.
- Docs: Updated API documentation to reflect program behavior filtering.

app/src/components/ToolCard.tsx

@@ -1,10 +1,10 @@
 import { Link } from "react-router-dom"
 import { Terminal } from "lucide-react"
-import type { ToolSummary } from "@/types"
+import type { ProgramSummary } from "@/types"
 import { runnerLabel } from "@/lib/labels"
 
 interface ToolCardProps {
-  tool: ToolSummary
+  tool: ProgramSummary
 }
 
 export function ToolCard({ tool }: ToolCardProps) {