Add squash-history Makefile target to collapse git history into a single commit

[Copilot]

Addresses the request to eliminate all previous commits, leaving a single commit representing the current repository state.

Changes

• Makefile — New squash-history target using the orphan branch technique:

  • Creates branch clean-history with no prior history (git checkout --orphan)
  • Stages all files and creates a single "Initial commit (squashed history)" commit
  • Prints the force-push command needed to apply the clean history to main

• README.md — New Git History Management section covering:

  • make squash-history usage
  • Equivalent manual git steps
  • Force-push warning for shared branches

Usage

make squash-history
# then, when ready to overwrite main:
git push --force origin clean-history:main

Note: Force-pushing rewrites public history. Coordinate with all collaborators before applying to a shared branch.

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[paraskuk]

ok