Summary

Adds a user-facing "Generate LODs" toggle to the publish settings dialog. When enabled, the publish request sends publishFormat: 'ssog' instead of 'sog', telling the server pipeline to decimate the PLY into LOD chunks (streaming SOG) rather than producing a single SOG.
The toggle is visible in both new-scene and republish flows and defaults to ON when both:

• the scene contains ≥ 1,000,000 splats, and
• the unioned scene world-bound exceeds 16 m on at least 2 axes.
  Otherwise it defaults to OFF, preserving today's single-SOG behavior.
  Changes:
• src/publish.ts: extended PublishSettings with generateLods; both doPublish and doRepublish payloads now derive publishFormat from it.
• src/ui/publish-settings-dialog.ts: new BooleanInput row, default computed from splat count + world-bound extents, threaded into the resolved PublishSettings. The row is hidden when republishing animation-only (no model upload).
• static/locales/*.json: added popup.publish.generate-lods for all 9 supported languages.
  Test plan:
• Load a small PLY (<1M splats or compact bounds) → toggle defaults OFF; publish → publishFormat: "sog" in request.
• Load a large outdoor PLY (≥1M splats and ≥2 axes >16 m) → toggle defaults ON; publish → publishFormat: "ssog".
• Republish an existing scene with the toggle on → PUT /splats/:id/republish body carries publishFormat: "ssog".
• Toggle off on a large scene before publishing → request still sends "sog".
• Republish animation-only (Override Model off) → Generate LODs row is hidden.
• Switch UI language → label renders the localized string.