chore: add notebook/MCP telemetry events

[emrberk]

Adds console telemetry for notebooks and the MCP bridge so we can see how these features are actually used. No functional changes — every emit is a fire-and-forget trackEvent wrapped around existing handlers, batched through the existing IndexedDB send pipeline.

What's tracked

Notebook interactions — create/duplicate, layout mode, cell add/delete/duplicate/move/rename/run/draw, resize and size-reset (gesture end only, never per tick), view changes and maximize, chart settings (open/save/cancel, save-blocked, type change, reset-to-auto), markdown apply, variables popover, result-tab switching, onboarding modal funnel (open/step/close, including Escape/overlay dismissals).

MCP lifecycle — pairing prompted/accepted/declined (with granted permission level), manual pair, connect/disconnect/connect-failed, permissions changes, setup-command copy, agent-changes popper, status popover. Intentional teardowns (user disconnect, re-pair) are excluded from mcp.disconnected so the event only counts real drops.

MCP tool calls — one event per call, named per tool (mcp.add_cell, mcp.run_query, …), emitted after dispatch with an outcome (ok / denied / tool_error / dispatch_error / aborted), a denial reason code where applicable (permission vs. freshness gate), and duration. Unrecognized tool names emit mcp.unknown_tool with the name capped at 100 chars.

Implementation notes

• Outcome classification lives in a new tested util (ConsoleEventTracker/mcpToolEvents.ts): it prefix-matches the known denial message constants and deliberately does not parse serialized tool results.
• Tool-name → event mapping is derived from the enum values; unit tests cover classification, mapping, and the permission-level hierarchy.
• Payloads are bounded enums, counts, and booleans only — no SQL text, table/cell names, variable values, tokens, or error messages leave the browser.

🤖 Generated with Claude Code