GeezerVison

Stacked on #29891.

Removes dead props and a redundant null check from the tool-call rows, and fixes one blank-label bug.

• ToolCall.tsx: deleted four props that no caller in site/src passes, including stories and tests: Root.view, Root.onViewChange, Label.shimmerWhenActive (always the default true), and Header.headerClassName. Root stays controllable with expanded.
• ProcessOutputTool.tsx: modelIntent ? sanitizeExecuteModelIntent(modelIntent, cmd) : "" becomes a direct call. sanitizeExecuteModelIntent already returns "" for undefined.

Behavior change (separate commit): in GenericToolRenderer (Tool.tsx), the label was modelIntent ? formatModelIntentLabel(modelIntent) : <ToolLabel />. model_intent is the raw string from the model, so it can be whitespace only. In that case formatModelIntentLabel returned "" and the header showed a blank label. It now uses formatModelIntentLabel(modelIntent) || <ToolLabel />, so blank intents fall back to the default tool label. A new Vitest case in Tool.test.tsx covers this: it fails without the fix and passes with it. It checks the header button's accessible name, which is the non-visual result of the label.

Overlap: #29894 also edits Tool.tsx. This PR changes only the label expression in GenericToolRenderer.

Part of the AgentsPage nullability cleanup; see #29888 for the methodology.

Verified: pnpm lint:types, check, lint:oxlint, lint:compiler, lint:knip, pnpm test src/pages/AgentsPage (1618 passed), and pnpm test:storybook src/pages/AgentsPage/components/ChatElements/tools/ (12 files, 230 passed).

This PR was generated by Coder Agents on behalf of @DanielleMaywood.