Add local blink parity script with divergent-file re-check

[TomasVotruba]

What

Adds blink/bin/parity.sh - a local version of the blink_parity_laravel / blink_parity_mautic CI workflows, for the tight iteration loop while closing a blink gap.

It runs the same all-sets ECS config both ways on two identical copies of a real project, then diffs the trees:

• bin/ecs check --fix --blink (Go binary)
• bin/ecs check --fix (PHP engine)

The files whose output differs are recorded to parity.<project>.txt. On the next run, --only re-checks just those files instead of the whole tree - so after a full run you iterate against the handful of divergent files rather than re-scanning thousands.

Usage

blink/bin/parity.sh laravel          # full run, refresh parity.laravel.txt
blink/bin/parity.sh mautic           # full run, refresh parity.mautic.txt
blink/bin/parity.sh laravel --only   # re-check only last run's divergent files
blink/bin/parity.sh laravel --fresh  # re-clone the project checkout

The project is cloned once into $TMPDIR and reused. --only passes the recorded file list as explicit path args to both engines (CheckCommand ...$paths overrides the config sources for both the PHP and blink paths), and rewrites parity.<project>.txt with whatever still diverges - so the list shrinks as gaps close.

Per-project file names (parity.laravel.txt, parity.mautic.txt) keep the two projects from clobbering each other. Both are gitignored.

Notes

• No PHP changed, so phpstan/rector/check-cs are unaffected.
• Verified: blink engine runs end-to-end on a laravel checkout (3035 files); the record / --only re-check logic verified on synthetic trees (full run lists both divergent files; after fixing one, --only shrinks the list to the remaining file).