W2.1 — Replace TooManyToolsWarning with DynamicToolsStatus

[edelauna]

Context

Once dynamic loading is on, the existing "Too many tools enabled" warning is wrong (most users will never see >50 tools attached at once — that's the point). It's also actively misleading because it suggests a problem when the system is working as designed. Replace it with a positive status indicator.

Partially closes: RooCodeInc#11155 (MCP tool calls clutter UI — by removing the dead warning).

Developer Notes

• Replace webview-ui/src/components/chat/TooManyToolsWarning.tsx with DynamicToolsStatus.tsx (same slot, same hook surface).
• Hook: useDynamicToolStatus() returns { attachedCount, totalScoped, mode: "all" | "dynamic" } from the new state slice the extension publishes (see W1.4 — the API tools array length is already known per turn).
• Render rules:
  • mode === "all" (under threshold): render nothing.
  • mode === "dynamic": render "N of M MCP tools attached this turn" with a click-through that expands to show the attached tool names.
• Remove i18n strings tied to the old warning (chat.tooManyTools.*); add new ones for the status indicator.
• Files: webview-ui/src/components/chat/DynamicToolsStatus.tsx (new), webview-ui/src/hooks/useDynamicToolStatus.ts (new), delete TooManyToolsWarning.tsx and useTooManyTools hook.
• Validation: with <50 tools enabled, no indicator visible; with >50, indicator shows accurate counts; click-through expands list and lists the tools currently in the API array.