build: switch pre-commit hooks to prek

[wesm]

Summary

• Replace hand-rolled .githooks/pre-commit script with prek for managing pre-commit hooks (matching roborev setup)
• make lint now runs golangci-lint run --fix to auto-fix formatting issues on commit
• New make lint-ci target preserves the no-fix behavior for CI

Test plan

• brew install prek && make install-hooks installs the hook
• prek run --all-files passes
• Committing triggers the golangci-lint hook with auto-fix

🤖 Generated with Claude Code

[roborev-ci]

roborev: Combined Review (1722785)

Verdict: Changes are mostly sound, but there are 2 medium-severity regressions in hook installation behavior that should be addressed before merge.

Medium

• Makefile:222
make install-hooks now runs prek install without -f. In repos that already have the previous pre-commit hook installed, this can fail to replace the existing hook or leave the old hook in place. prek migration guidance requires force-replacing an existing hook during this transition.
  Suggested fix: change this to prek install -f and document that the command replaces any existing hook.

• Makefile:222
  The previous implementation resolved the active hooks directory with git rev-parse --git-path hooks, which works for linked worktrees and non-default core.hooksPath setups. Replacing that with plain prek install appears to drop that logic, which risks installing into .git/hooks/ instead of the directory Git is actually using.
  Suggested fix: preserve the resolved hook-path behavior, or invoke prek through a wrapper/flow that installs into the path returned by git rev-parse --git-path hooks.

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Synthesized from 3 reviews (agents: codex, gemini | types: default, security)

[roborev-ci]

roborev: Combined Review (11d5533)

Verdict: Changes are mostly sound, but there is one medium-severity regression in lint target behavior that should be addressed before merge.

Medium

• make lint now mutates files instead of acting as a check
  Location: Makefile:171
  Changing make lint to golangci-lint run --fix ./... turns a previously read-only validation target into a mutating command. Any CI job or automation still calling make lint can now rewrite files silently and may pass on fixable lint violations instead of failing, which weakens lint enforcement.
  Suggested fix: Keep lint as a non-mutating check target and introduce a separate lint-fix target for local/pre-commit use, or update all existing automated callers to use make lint-ci in the same change.

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Synthesized from 3 reviews (agents: codex, gemini | types: default, security)

[wesm]

Invalid