refactor(web): rename "History" tab/feature to "Protocol" (#1623)

Rename the web client's History tab and its supporting code to Protocol
so the feature reads as the MCP "Protocol" view.

- Tab renders as "Protocol"; INSPECTOR_TAB_IDS, InspectorView tab
  constants/MonitorTab, TAB_UI_REGISTRY key, and navigation.ts tab id all
  updated to Protocol.
- Rename components + folders: HistoryScreen -> ProtocolScreen,
  HistoryListPanel -> ProtocolListPanel, HistoryEntry -> ProtocolEntry,
  HistoryControls -> ProtocolControls, historyUtils -> protocolUtils
  (plus their tests and stories, and exported types).
- Rename App/InspectorView plumbing: historyUi, pinnedHistoryIds,
  on*History* handlers/props, replayHistoryRequest,
  isReplayableHistoryMethod, sort/compact scopes, etc. -> Protocol names.
- Export filenames use the "protocol" slug (buildExportFilename +
  ExportKind).

Preserved (per issue #1623 decisions):
- The in-panel section discriminator keeps its "pinned" | "history"
  values, and the sub-sections stay labeled Pinned / History.
- window.history and core message-log/replay concepts are untouched.

npm run ci passes (format, lint, build, unit tests, >=90 per-file
coverage gate, smoke, Storybook).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BrihGWcrM9JGRyu41nzZYw

clients/web/src/components/elements/EmbeddableScrollArea/EmbeddableScrollArea.tsx

@@ -20,7 +20,7 @@ export interface EmbeddableScrollAreaProps {
 }
 
 /**
- * The scroll region shared by the Logs / History / Network stream panels, which
+ * The scroll region shared by the Logs / Protocol / Network stream panels, which
  * render both full-size (their own tab) and embedded (the monitoring column).
  * Centralizes the one layout difference between those two hosts.
  */