chore!: next.js 16 prep: bump eslint-config-next + @next/eslint-plugin-next to v16 (#932)

[frano-m]

Summary

Part of #884 (Next.js 16 upgrade plan).

Bumps eslint-config-next + @next/eslint-plugin-next to v16, which forces ESLint 8→9, which cascades into multiple plugin updates required to keep the lint stack working under flat-config + ESLint 9.

Core bumps

• eslint: ^8.57.1 → ^9
• @eslint/js: ^8.57.1 → ^9
• eslint-config-next: ^15.5.13 → ^16
• @next/eslint-plugin-next: ^15.5.13 → ^16
• Drop the ESLINT_USE_FLAT_CONFIG=true env-var prefix from the lint script (ESLint 9 makes flat config the default).

Plugin cascade (forced by ESLint 9 compat)

• eslint-plugin-sonarjs: ^0.25.1 → ^1 (v0.25 uses removed context.getScope API).
• eslint-plugin-react-hooks: ^5.2.0 → ^7.
• eslint-plugin-sort-destructure-keys: ^2 → ^3 (peer range widened to ESLint 9/10).
• eslint-plugin-jsdoc: ^61.5.0 → ^63.
• @typescript-eslint/eslint-plugin: ^8.50.0 → ^8.59.0 (minor).

Plugin replacements

• eslint-plugin-typescript-sort-keys → eslint-plugin-perfectionist (the former is abandoned; pinned to ESLint 7-8). Replaces our two rules:
  • typescript-sort-keys/interface → perfectionist/sort-interfaces
  • typescript-sort-keys/string-enum → perfectionist/sort-enums
• eslint-plugin-eslint-comments → @eslint-community/eslint-plugin-eslint-comments (community fork; the original was last released in 2022 and uses old ESLint internals). Drop-in (rule names unchanged: @eslint-community/eslint-comments/require-description).

Flat-config adjustments

• eslint-config-next v16 ships a native flat config that doesn't roundtrip cleanly through FlatCompat (circular JSON during schema validation). Direct-imported as import next from "eslint-config-next" and spread before the compat.config(...) block.
• eslint-plugin-sonarjs v1 same situation. Direct-imported as import sonarjs from "eslint-plugin-sonarjs" and added as sonarjs.configs.recommended.

Node version bump

• Repo pin: 22.12.0 → 22.13.0 (package.json#engines + 3 CI workflow refs + Copilot instructions doc). eslint-plugin-jsdoc@63 requires node ^22.13.0 || >=24; staying on 22.12.0 would emit EBADENGINE warnings. Same LTS line, patch-level bump only.

Rule-set notes

• New react-hooks v7 rules disabled. v7 ships React-Compiler-aware checks (refs, immutability, set-state-in-effect, incompatible-library, static-components) that surface ~20 real anti-patterns across the codebase. These are out of scope for a tooling PR — disabled here with a comment, follow-up ticket to be filed.
• sonarjs/cognitive-complexity restored explicitly at threshold 15. sonarjs v1's recommended preset silently dropped this rule (the rule's meta.docs.recommended flag was lost during the v1 rewrite, a discrepancy with the package README). Restoring preserves the coverage we had under v0.25. Documented in an inline comment.

Source-file changes (pure cleanup, no behavior change)

ESLint 9 enables report-unused-disable-directives by default. --fix removed several stale eslint-disable comments that were orphans from past refactors: valid-jsdoc (rule removed in ESLint 9), @typescript-eslint/no-explicit-any (the any had been taken out of the code), @typescript-eslint/no-empty-function (function bodies no longer empty in a way the rule cares about), sort-keys (keys had been alphabetized at some point).

Test plan

• npm run lint — clean (one pre-existing no-html-link-for-pages informational notice from @next/eslint-plugin-next — findable-ui is a library, not an app)
• npm run check-format — clean
• npm run test-compile — clean
• npm test — 447/447 pass
• Local-link smoke test in data-biosphere (fran/x-nextjs-test, anvil-cmg dev) — dev server compiles + runs cleanly against the patched findable-ui

Compatibility scope (revised)

This PR lands a stack compatible with ESLint 9. Forward-compat with ESLint 10 will require additional work: eslint-plugin-sonarjs@1 only declares peer support for ^8 || ^9 — a bump to eslint-plugin-sonarjs@4 (or whichever version officially adds v10) will be needed before adopting ESLint 10. Filing as a follow-up.

Closes #932

[Copilot]

Pull request overview

This PR updates the repository’s linting toolchain as part of the Next.js 16 upgrade plan by bumping eslint-config-next/@next/eslint-plugin-next to v16 (requiring ESLint 9) and adjusting the flat-config setup and plugin set to remain functional under ESLint 9.

Changes:

• Bump ESLint core + Next ESLint config/plugin to v16 and update the supporting ESLint plugin stack for ESLint 9 compatibility.
• Update eslint.config.mjs to direct-import Next + SonarJS flat configs, replace deprecated plugins (eslint-comments fork, sort-keys plugin replacement), and reapply/adjust rules.
• Remove stale eslint-disable directives across the codebase now that ESLint 9 reports unused disables by default.

Reviewed changes

Copilot reviewed 12 out of 13 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
eslint.config.mjs	Updates flat-config composition (direct Next + SonarJS configs), swaps plugins (perfectionist, eslint-comments fork), and adjusts rules for ESLint 9.
package.json	Bumps ESLint/Next ESLint packages and updates/replaces several ESLint plugins; simplifies lint script for ESLint 9 flat-config default.
package-lock.json	Locks the updated ESLint/Next lint stack and transitive dependency changes.
src/theme/common/components.ts	Removes now-unused sort-keys disable comments.
src/providers/fileManifestState.tsx	Removes unused no-empty-function disable.
src/providers/exploreState.tsx	Removes unused no-empty-function disable.
src/entity/service/model.ts	Removes an unused no-explicit-any disable in a signature where it no longer applies.
src/config/utils.ts	Removes an unused no-explicit-any disable in a signature where it no longer applies.
src/components/Table/common/utils.ts	Removes unused no-empty-function disable in a callback config object.
src/components/MarkdownRenderer/rehypeHighlight.ts	Removes unused sonarjs/cognitive-complexity disable.
src/components/Index/table/hook.ts	Removes unused inline sonarjs/cognitive-complexity disable.
src/components/Filter/components/adapters/tanstack/ColumnFiltersAdapter/columnFiltersAdapter.tsx	Removes unused no-unused-vars disables where underscore-prefixed args are already ignored.
src/components/common/Paper/paper.styles.ts	Removes legacy valid-jsdoc disable/enable comments (rule no longer relevant).

[Copilot]

Pull request overview

Copilot reviewed 18 out of 19 changed files in this pull request and generated no new comments.