Adopt the verified Fleet Ultracite lint baseline

[sarthakagrawal927]

Context

Fleet Workspace issue sass-maker/fleet-workspace#249 is rolling the verified Ultracite-backed Biome baseline beyond the Drank pilot in repository-owned changes. LoopTV is a clean, independently operable Biome project and is the next bounded adoption.

Scope

• Add exact ultracite@7.10.2 as a development-only tool dependency.
• Extend the core, React, Astro, and Vitest Biome presets while retaining explicit LoopTV compatibility exceptions.
• Preserve project-owned AGENTS.md; do not run write-mode formatting, rebuild the catalog, or broadly rewrite source.
• Do not change production dependencies, catalog data, playback behavior, deploy commands, secrets, or production configuration.

Acceptance

• Native lint, format, typecheck, unit tests, build, and docs validation pass.
• Fleet's read-only parity report classifies LoopTV as aligned.
• Dependency/lockfile changes are limited to the exact development-only tool and its transitive lockfile entries.
• Incompatible diagnostics become explicit local exceptions rather than a broad source rewrite.

Tracks sass-maker/fleet-workspace#249.

[sarthakagrawal927]

Completed by merged PR #34 (c75987b). The automatic Pages preview workflow was cancelled; CI passed and no deployment ran to completion.