Replace household NPCs with distinct residents and idle animation

[axelpey]

Replace the three stationary household scans with the approved stylized residents: Alex with auburn hair and freckles, Blake with curls and a beard, and Casey with silver hair and glasses. Each has distinct facial geometry, skin tone, clothing, and staggered breathing, weight shifts, blinks, and head/gaze motion. Refined heads use more natural adult proportions, continuous sculpted cheek/jaw/nose surfaces, recessed eye sockets, finer eyelids and lips, scalp-conforming hair, and subtle skin/beard shading. The characters remain stylized.

The asset build now generates both the animated GLBs and matching MuJoCo OBJ/palette textures from tracked source. The viewer samples the Idle clip on interpolated simulation time, preserving pause/reset behavior and world placement. Resident IDs, names, voices, heights, challenge placements and orders are unchanged. Loading, placement previews, removal/re-add and scene disposal are covered, including late asset arrivals.

Scope: idle motion is cosmetic in Three.js. MuJoCo RGB/depth use the new characters in their standing pose, and collision bodies remain kinematic. This does not add autonomous walking or roaming.

Validation:

• 4 focused viewer tests passed: matching geometry/height, head proportions and color export, loop continuity, planted feet, animation lifecycle, old-bundle fallback and late-load cleanup.
• All 76 host-side tests passed; viewer typecheck/build and pre-commit checks passed.
• Exercised the actual SimScene renderer with the apartment assets and existing resident placements in Chrome: inspected all three residents; pause/resume, removal/replacement and reset worked without browser errors.
• Compiled and rendered all three generated models with MuJoCo.

The full ROS/agent workflow and multi-architecture asset-image build were not run locally. Viewer validation is now included in CI.