#994 ci: add aireceipts auto-attach hook (two-file kit)

Adds the second file of the aireceipts two-file kit: the .claude/settings.json PreToolUse hook that auto-attaches a receipt ref on push, so receipts generate automatically (no manual command) and the existing pr-check workflow has something to post.

• The hook runs npx -y aireceipts-cli@latest hook pre-push; it never blocks your push (exits 0 on every path, no output) and only acts on a real branch push to origin.
• This repo runs no other refs/receipts/* producer, so there is no collision.
• Remove anytime by deleting/reverting the file.

Part of the org-wide aireceipts dogfood (v0.6.0).

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Summary by cubic

Adds a .claude/settings.json PreToolUse hook that auto-attaches an aireceipts receipt on push. Receipts generate automatically so the pr-check workflow has data to post.

• New Features
  • Runs npx -y aireceipts-cli@latest hook pre-push with a 60s timeout (cold-cache headroom).
  • Never blocks pushes (always exits 0, no output).
  • Only runs on real branch pushes to origin.

Summary by CodeRabbit

• Chores
  • Added an automated pre-push hook to run an aireceipts-cli pre-push check before changes are sent.
  • The hook includes a timeout to keep the pre-push step responsive.
  • Helps catch issues earlier and improves consistency in the local development workflow.