✨ feat(eslint): enforce PascalCase use-case file naming

[cteyton]

Explanation

Enforce the use-case file naming convention automatically. Use-case files under
packages/**/application/useCases/ followed two conflicting conventions — the
desired PascalCase form (AddGitRepoUseCase.ts) and a legacy lowercase-suffix
form (addGitRepo.usecase.ts).

This PR:

• Adds a custom workspace ESLint rule packmind/use-case-filename (new eslint/
  plugin) that bans the legacy .usecase suffix and requires PascalCase. It is
  unit-tested with RuleTester and wired into the root flat config as error,
  so npm run lint now fails on any *.usecase.ts file.
• Renames the 132 existing legacy files (sources + specs/tests) across 6
  packages to PascalCase, where each file name matches its exported class name.

ArchUnit was considered and rejected: it is JVM-only and its TS port targets
dependency/layer rules, not filename casing. A custom ESLint rule plugs straight
into the existing npm run lint pipeline with zero new runtime deps.

Type of Change

• Bug fix
• New feature
• Improvement/Enhancement
• Refactoring
• Documentation
• Breaking change

Affected Components

• Domain packages affected: llm, recipes, deployments, skills, git, standards (file renames); new eslint-rules tooling project
• Frontend / Backend / Both: Backend / tooling
• Breaking changes (if any): None — renames are internal; all imports/barrels updated, no public package API changes

Testing

• Unit tests added/updated
• Integration tests added/updated
• Manual testing completed
• Test coverage maintained or improved

Test Details:

• New RuleTester suite for packmind/use-case-filename (9 cases: PascalCase + helpers like index.ts/utils.ts/shared/* valid; *.usecase.ts / *.usecase.spec.ts invalid; one case locks the exact error message wording).
• Full repo verification, all green:
  • npm run lint → 31 projects, 0 errors
  • npm run build → 27 projects
  • npm run test → 26 projects (exit 0)
• Manual probe: a temporary tmpProbe.usecase.ts triggers the rule with a clear, actionable error suggesting TmpProbeUseCase.ts, then removed.

TODO List

• CHANGELOG Updated
• Documentation Updated

Reviewer Notes

• The rule only flags the forbidden .usecase suffix (not a positive PascalCase
  requirement), so helper files inside useCases/ are never false-positives.
• Each renamed file matches its exported class name — including bare classes that
  don't end in UseCase (e.g. commitToGit.usecase.ts → CommitToGit.ts).
• The rule's files glob is project-relative (**/application/useCases/**/*.ts)
  because nx lint runs eslint . with cwd = each project dir.
• The rule + plugin are authored as CommonJS; a small local eslint/eslint.config.mjs
  allows require() in those files so the inferred eslint-rules:lint target passes.
• Renames are one commit per package for easy review.

[greptile-apps]

Too many files changed for review. (170 files found, 100 file limit)

[cteyton]

Review feedback addressed

Resolved the three findings by tightening the convention to UseCase (capital C) everywhere, rather than softening the message:

#1 — message contradicted the applied convention. The rule now positively enforces the convention via AST, so the message is true:

• legacy .usecase filename → legacyFilename
• mis-cased Usecase filename → filenameCasing
• exported class ending Usecase → classCasing
• exported (non-Error) class missing the suffix → classMissingSuffix

The 4 bare git classes (CommitToGit, HandleWebHook, HandleWebHookWithoutContent, GetFileFromRepo) were renamed to …UseCase, so reintroducing commitToGit.usecase.ts now correctly points at CommitToGitUseCase.

#2 — .tsx suggested as .ts. Fixed: the original extension is preserved in the suggestion (covered by a widget.usecase.tsx → WidgetUseCase.tsx test case).

#3 — Usecase vs UseCase left inconsistent. Unified: 86 classes (82 …Usecase + 4 bare) renamed to …UseCase, classes + files + all references, one commit per package (recipes, skills, deployments, standards, git). 0 Usecase classes/files remain under packages/**/application/useCases/.

Scope note: the rule runs only on packages/ — apps/cli co-locates genuine non-use-case classes (*DiffStrategy implements IDiffStrategy) under useCases/, which a positive rule must not flag.

Verified: nx test eslint-rules (14 cases) ✓, npm run lint (31 projects, 0 errors) ✓, npm run build (27) ✓, npm run test (26) ✓.

[sonarqubecloud]

Quality Gate passed

Issues
75 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
9.1% Duplication on New Code

See analysis details on SonarQube Cloud