feat: selectable visible water cells and public inspection records

[ael-dev3]

Summary

Adds PR4 visible Water interaction and read-only inspection on top of the exact PR3 Worker Command Center head (0d4418e).

• raycastable clear/haze ocean and river cells mapped deterministically from indexed face ranges to canonical cellKey / bodyId / regime / coordinate
• full-fog ocean cells and unexpected lake rows fail closed; no browser-local water identity or gameplay authority is created
• water selection/hover uses two reusable outline overlays (no per-cell meshes) and preserves the existing worker → wagon → castle → static site → water → terrain pick order
• camera focus, durable interaction state, keyboard focus, Escape behavior, mobile-sized drawer, reduced-motion-safe presentation, static fallback navigator parity
• bounded one-row-per-river navigator with source/mouth focus actions
• read-only panel includes public river reach/source/mouth/flow/depth/fog/underlying-cell context and an explicit gameplay boundary

Art gate

No approved high-resolution Water record art was found in the repository or approved asset history during implementation. The panel therefore uses a deliberately restrained programmatic water illustration tagged data-art-status="programmatic-placeholder" and data-art-provenance="approved-water-record-art-unavailable". Replace only after approved art is supplied; no guessed Downloads/Desktop asset is used.

Validation

• TypeScript project build passes.
• Focused interaction, water layer, presentation, accessibility, and Realm quality regression tests pass (63 tests).
• Vite production bundle succeeds.
• No SpacetimeDB schema, seed, publication, activation, deploy, or release changes are included.

Review notes

The branch is intentionally a draft and is based on PR3's exact head. Please review projection/topology assumptions and the art gate before any merge or live activation.