MBTI-INDEX-52: fix streamed preflight namespace isolation

[fermatmind]

What changed

• Corrects the PHP namespace replacement literals used to isolate the streamed INDEX-52 package and service classes.
• Adds an executable regression test proving both source namespaces are replaced exactly once.

Why

• Read-only production preflight run 30267578476/1 failed locally while building the streamed runner because the workflow searched for two literal backslashes instead of one.
• The failure occurred before the production SSH read step; no production action or write occurred.

Validation

• cd backend && php artisan test tests/Sre/MbtiIndex52ProjectionRepairPreflightWorkflowTest.php
• cd backend && ./vendor/bin/pint tests/Sre/MbtiIndex52ProjectionRepairPreflightWorkflowTest.php
• actionlint .github/workflows/mbti-index52-projection-repair-preflight.yml
• Exact workflow-equivalent streamed runner generation followed by php -l
• git diff --check

Deferred items

• Production preflight rerun remains deferred until this focused repair is merged into latest main.
• No CMS/database write, publication/indexability mutation, sitemap/llms submission, search submission, deploy, restart, or remote file write is included.

Repository rule impact

• No authority boundary changes. This only repairs the existing read-only backend control-plane runner.

[fermatmind]

@codex review exact head af712e8

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. Delightful!

Reviewed commit: af712e8e4b

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