v0.34.1

Security patch: the fleet's merge brake, generalized. Ships the #598 fix alone so it reaches
installs immediately: no session launched by the fleet can merge its own PR unless the human
explicitly opts in.

Fixed

• Fleet sessions launched with -Parallel -Launch now stop at a reviewed PR by default (#598).
  Previously, a session launched without an expert contract could merge its own PR with no review:
  it was running with --permission-mode bypassPermissions, was briefed to call Board-Merge.ps1,
  and nothing in the tool layer refused it. On 2026-08-03, two such sessions merged their own PRs
  with reviews: [] and no [abios-review] record; post-merge review found that one PR had not
  built the central item of its issue's DoD. Fix: all -Launch and -Fleet sessions now arm the
  brake by default — Resolve-LaunchBrake returns $true (stop at PR) unless -AllowMerge is
  explicitly passed or the caller explicitly passes -StopAtPR:$false (an expert contract that
  allows merging). This aligns the plain fleet path with the expert path, where the brake was
  already mechanical. The -Relaunch path receives the same default. Three new Pester tests
  cover: default brakes, -AllowMerge opt-out, explicit -StopAtPR:$false honored.