Split the oversized client entry chunk

[ApocDev]

Problem

The production build succeeds, but Vite reports the main client entry chunk at 768.94 kB (225.97 kB gzip), above its 500 kB warning threshold.

Follow-up

• Inspect the entry chunk composition.
• Lazy-load route- or feature-specific heavy dependencies where that reduces initial startup cost.
• Add a lightweight bundle-size regression check or documented baseline.
• Re-run the production build and record before/after parsed and gzip sizes.

Surfaced while completing #138; separate from its SQLite, solver, mutation, and recurring-RPC work.