fix: remove runs tab from canvas log sidebar

[forestileao]

Summary

This PR removes the Runs section from the bottom canvas log sidebar and keeps only Errors and Warnings there.

Changes

• removed the Runs tab from CanvasLogSidebar
• removed the collapsed bottom-bar Runs button that opened the log sidebar
• removed run-specific bottom-sidebar props, state, and rendering from CanvasPage
• removed run-log entry generation and websocket-driven run log plumbing that only existed for the bottom sidebar
• deleted now-unused run-log helper code and related tests
• updated the CanvasLogSidebar story to reflect the new errors/warnings-only behavior

[superplanehq-integration]

👋 Commands for maintainers:

• /sp start - Start an ephemeral machine (takes ~30s)
• /sp stop - Stop a running machine (auto-executed on pr close)

[cursor]

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[forestileao]

👍