Activation fixes for the single-session presence gate. Two bugs blocked it,
both caught by live testing after all units were green:
1) Wrong branch key. presence_gate used Path.cwd().name, but under the Claude
Code bridge the hook process cwd is the project root, so every session keyed
to "AIPass": the gate never enforced one-live-session-per-branch and would
have rejected sessions project-globally (any 2nd interactive session in any
branch). Now _resolve_branch(hook_data) reads the event payload's cwd (the
real session dir) and walks up to the branch root (.trinity/ or apps/),
mirroring branch_loader. Applied in handle() and handle_stop().
2) Block never reached Claude Code. engine.dispatch() returned only stdout, so
the bridge could not surface a non-zero exit. dispatch() now returns
(stdout, exit_code) and the bridge exits with it on a block. Pre-existing gap
affecting every block hook on every event; now fixed engine-wide. An
intentional block (exit 2 + {"decision":"block"}) propagates; a crashing hook
(exit 2, non-JSON stdout) is logged and falls through, so the gate fails open.
Proven: 110 hooks unit tests pass (6 new for branch resolution); seedgo @hooks
100%, no type errors. Live bridge end-to-end (real live holder + real bridge):
duplicate into a held branch -> exit 2 + block reason naming the branch; a
different free branch -> exit 0 (per-branch isolation intact). Gate remains
dormant: not yet wired into provider settings.
Design: DPLAN-0225 / FPLAN-0289 P1 activation. Build by @hooks.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CqoxFdbDMirzkQ5kjRVVos
