INTER-2222: Upgrade to ESLint v10 flat config

[erayaydin]

Use @fingerprintjs/eslint-config-dx-team@2.0.0 which requires ESLint v10 and exports a flat config array.

Dependency changes

Package	Before	After	Reason
eslint	8.57.0	^10.4.1	Required by dx-team config v2
@fingerprintjs/eslint-config-dx-team	^0.1.0	^2.0.0	ESLint upgrade and flat config
eslint-config-next	14.1.3	^16.2.0	v14 uses @rushstack/eslint-patch which fails on ESLint v10; v16 is flat-config native
eslint-plugin-react-hooks	^4.6.0	^7.0.0	Required peer of eslint-config-next@16
eslint-plugin-prettier	^5.5.5	removed	Bundled in dx-team config
@eslint/eslintrc	-	^3.0.0	⚠️ Needed for FlatCompat in examples/preact. We can consider moving this to the example package.json file
typescript-eslint	-	^8.60.0	Explicit dep for parser override in root config

Config notes

settings.react.version: '18.2' instead of 'detect': the detect path in eslint-plugin-react@7.37.x calls context.getFilename() which was removed in ESLint v10.

Parser override for .js files: eslint-config-next@16 sets @babel/eslint-parser for all files, then restores @typescript-eslint/parser only for .ts/.tsx. The babel parser's eslint-scope@5.x scope manager lacks the addGlobals() method ESLint v10 requires, so we re-apply @typescript-eslint/parser for .js/.jsx files.

examples/preact — uses FlatCompat to wrap eslint-config-preact (no flat config support). plugin:@typescript-eslint/recommended is replaced with tseslint.configs.recommended (unified package v8) to support TypeScript 5.9

Code changes

@typescript-eslint/no-empty-object-type

Empty object type {} is now flagged; object is the correct replacement when you mean "no specific props".

no-promise-executor-return

__tests__/helpers.tsx

// before
new Promise(resolve => setTimeout(resolve, ms))
// after
new Promise(resolve => { setTimeout(resolve, ms) })

@typescript-eslint/no-non-null-assertion

DOM querySelector calls in tests suppressed with eslint-disable-next-line. The elements are asserted to exist by the test setup.

@typescript-eslint/no-explicit-any

• Test props typed as { env?: { name: string } } instead of any.
• render(...args: any[]) -> render(...args: unknown[]).

@typescript-eslint/ban-ts-comment

The rule now requires a description when suppressing comments.

@typescript-eslint/consistent-type-assertions

• const mock = fn as FunctionComponent -> const mock: FunctionComponent = fn
• Unavoidable widening/narrowing casts suppressed with eslint-disable-next-line.

no-useless-constructor

Empty constructor removed. It provided no behaviour and is redundant when the parent's constructor signature is identical.

@typescript-eslint/no-require-imports

CJS file using require() suppressed with a file-level disable. The script runs in Node
before any bundler, and cannot use ESM (depends on Node.js version).

[github-actions]

⚠️ This PR doesn't contain any changesets. If there are user-facing changes, don't forget to run:

pnpm exec changeset

to create a changeset.

[github-actions]

Coverage report

St.❔	Category	Percentage	Covered / Total
🟢	Statements	83.08% (-0.13% 🔻)	108/130
🟡	Branches	63.77%	44/69
🟢	Functions	80% (-0.49% 🔻)	32/40
🟢	Lines	82.68% (-0.14% 🔻)	105/127

Test suite run success

21 tests passing in 15 suites.

Report generated by 🧪jest coverage report action from c38df46

Show full coverage report

St	File	% Stmts	% Branch	% Funcs	% Lines	Uncovered Line #s
🟢	All files	83.07	63.76	80	82.67
🟢	src	88.7	75.86	83.33	88.33
🟢	detect-env.ts	90	83.33	100	90	15,87
🟢	env.ts	100	100	100	100
🟢	env.types.ts	85.71	40	50	83.33	14
🟡	...nt-context.ts	75	100	0	75	8
🟡	get-env.ts	60	0	100	60	8-9
🟢	ssr.ts	100	100	100	100
🟢	...sitor-data.ts	95.65	100	80	95.65	101
🟢	src/components	92.3	61.53	90.9	92.1
🟢	...-provider.tsx	91.17	58.33	90	90.9	54,59,97
🟢	...vironment.tsx	100	100	100	100
🟡	src/utils	58.62	42.85	63.63	58.62
🟡	...-is-truthy.ts	50	50	100	50	3
🟡	to-error.ts	66.66	50	100	66.66	6
🟢	use-const.ts	100	50	100	100	5
🟢	...mise-store.ts	92.3	75	100	92.3	7
🔴	wait-until.ts	0	0	0	0	8-19