feat(framework+cli): Phase 2 PR 7 — pre-PR hook + devtrail init --hooks

[montfort]

Summary

Seventh of 8 PRs. Adds the opt-in friction layer that runs devtrail charter drift before git push. Per principle #6 (cognitive discipline > raw productivity), the hook is virtuous when consented to — never installed by default.

Framework

• dist/.devtrail/hooks/pre-pr.sh — bash hook that scans docs/charters/*.md for status: in-progress, runs devtrail charter drift <id> --range $UPSTREAM..HEAD for each, exits non-zero if any reports unaccounted drift. AILOG-suppression in the CLI (PR 3) silences alerts on paths already documented as risks. Default upstream is origin/main; override via DEVTRAIL_UPSTREAM env var. Manual install: cp .devtrail/hooks/pre-pr.sh .git/hooks/pre-push.

CLI

• New --hooks flag on devtrail init (default: false). After init succeeds, copies .devtrail/hooks/pre-pr.sh to .git/hooks/pre-push and makes it executable.
• Refuses to overwrite an existing pre-push hook (warns and continues without).
• Skips silently if the project isn't a git repository.

Behavior tradeoffs

• The hook short-circuits when devtrail is not in PATH, so adopters who haven't installed the CLI yet can still push without friction.
• The hook respects --no-verify (standard git escape hatch); documented use case: "drift was intentional, captured in AILOG, push anyway".

Test plan

• 4 unit tests in init::hook_tests:
  • install_pre_pr_hook_copies_and_makes_executable (happy path, asserts executable bit)
  • install_pre_pr_hook_skips_when_not_a_git_repo
  • install_pre_pr_hook_refuses_to_overwrite_existing
  • install_pre_pr_hook_errors_when_source_missing
• 382/382 tests pass.
• Bash syntax check passes (bash -n pre-pr.sh).

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