Restore eslint prefer-const rule

[allanjoseph98]

Probably disappeared in the linter switches

[icp1994]

Not that it matters but levenAndVal probably typo

PR Overview

This PR restores the ESLint rule "prefer-const" that was previously removed and adjusts variable declarations to use const where possible.

• Restores the "prefer-const" rule in the ESLint configuration.
• Converts several variable declarations from let to const across multiple files.
• Refactors the console handler to simplify destructuring assignments.

Reviewed Changes

File	Description
ui/eslint.config.mjs	Adds the "prefer-const" lint rule to enforce immutability.
ui/.build/src/console.ts	Refactors destructuring to extract values from parsed JSON more clearly.
ui/recap/src/slides.ts	Changes variable declaration from let to const for immutability.
ui/voice/src/move/voice.move.ts	Updates variable declaration from let to const in the lookup function.
ui/recap/src/util.ts	Updates array initialization from let to const.

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Comments suppressed due to low confidence (1)

ui/.build/src/console.ts:26

• [nitpick] Consider using direct destructuring (e.g., 'const [level, val] = Object.entries(JSON.parse(body));') to eliminate the intermediate variable 'levelAndVal' and improve clarity.

const [levelAndVal] = Object.entries<string>(JSON.parse(body));