Ticket(s) Closed

• None

What

• Align contributor/setup docs with the current repository tooling.
• Replace stale prek references with pre-commit.
• Remove dead PARADEDB_WITH_PG setup guidance.
• Pin the local ParadeDB image and formatter package versions.
• Fix the trailing-newline lint check and make RuboCop's target Ruby explicit.

Why

• The repo instructions had drifted from the actual scripts and automation.
• Local development was less reproducible than CI because the local ParadeDB image floated on latest.
• The trailing-newline workflow step was ineffective as written.
• Tooling metadata was too implicit for long-term maintenance.

How

• Update CONTRIBUTING.md, bin/setup, and scripts/run_paradedb.sh to match the current workflow.
• Pin formatter installs in the markdown and YAML lint workflows.
• Replace the newline check with a real tracked-file scan.
• Set TargetRubyVersion and disable extension suggestions in .rubocop.yml.

Tests

• bash -n on the changed shell scripts.
• Full bundle exec / CI execution was not run locally because this environment has Ruby 2.6, while the repo currently targets Ruby 4.0.0 and Bundler 4.0.3.