test(lib): cover agent-activity status labels (57→65 tests)

Extract TOOL_STATUS + statusFromPart from stores/events.ts into a pure
status-labels.ts (type-only Part import, erased at runtime; events.ts delegates).
8 tests pin the live 'what is the agent doing' labels: reasoning/text/known-tool
mappings, shared labels (search/edit groups), unknown-tool degrade to
'Running <tool>...', and the no-tool/unknown-type fallthroughs. typecheck clean.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/lib/status-labels.ts

@@ -0,0 +1,27 @@
+// Human-readable status labels shown while the agent works ("Searching codebase...").
+// Extracted from stores/events.ts so the mapping is unit-testable in isolation.
+// `import type` is erased at runtime, so this module pulls in no RN/SDK code.
+import type { Part } from "./sdk"
+
+// Tool status labels derived from part type.
+export const TOOL_STATUS: Record<string, string> = {
+  read: "Gathering context...",
+  list: "Searching codebase...",
+  grep: "Searching codebase...",
+  glob: "Searching codebase...",
+  webfetch: "Searching web...",
+  edit: "Making edits...",
+  write: "Making edits...",
+  apply_patch: "Making edits...",
+  bash: "Running command...",
+  task: "Delegating...",
+  todowrite: "Planning...",
+  todoread: "Planning...",
+}
+
+export function statusFromPart(part: Part): string {
+  if (part.type === "reasoning") return "Thinking..."
+  if (part.type === "tool" && part.tool) return TOOL_STATUS[part.tool] || `Running ${part.tool}...`
+  if (part.type === "text") return "Writing..."
+  return "Working..."
+}