Update code analysis tooling (ktlint, spotless, detekt) and add CI enforcement

Related PRs: #1206 #1207

**Summary**
Upgrade ktlint-gradle, spotless, and detekt to current stable versions, fix all pre-existing violations, and add a CI job to enforce linting on every PR.

**Motivation**
The project was running outdated code analysis tools with deprecated configuration syntax and 25 pre-existing detekt violations. There was no CI enforcement, so lint issues could slip through undetected.

**Acceptance criteria**
- [ ] Upgrade ktlint-gradle (11.0.0 → 14.2.0) and spotless (6.18.0 → 8.4.0)
- [ ] Update `.editorconfig` to new `ktlint_standard_*` rule syntax
- [ ] Modernise `detekt.yml` and fix all 25 pre-existing violations
- [ ] Add a CI job that runs `./codeAnalysis.sh` on every PR
- [ ] Install a git pre-commit hook for local enforcement

**References**
Closes #1206, #1207