[iamfatness]

Closes #439

Applies the 2026-10-23 owner tier ruling (dedicated VRAM: under 8 GB, 8-16 GB, 16 GB+) to the canvas default/offered ceiling and the multiview tile ceiling via a pure GpuTierPolicy fed by the existing GpuTierProbe band.

• Defaults apply only to never-saved profiles; saved canvas/tile values are kept verbatim and logged (gpu-tier-defaults tier=... override=...).
• Settings: canvas picker limited to the tier ceiling (current value always kept), new "Allow settings above this GPU's recommended limits" switch (persisted), tile NumberBox max bound to the ceiling (was a stale 8).
• Unknown VRAM = under-8 GB tier plus visible notice.
• Tile ceilings 16/25 are capped to the product's 10 Show Input slots until the wall supports more.
• 1751 shell tests pass (new GpuTierPolicyTests).

Not verified on real hardware; telemetry payload unchanged (override flag is log-only).

🤖 Generated with Claude Code