v2.6.0

Added

• sesh detection (HAVE_SESH) — finishing wiring Core already half-shipped.
  sesh (joshmedeski's smart tmux session manager) was already driven by the
  Ctrl-G shell widget (fzf.zsh), the prefix + f tmux popup (tmux-sesh.sh),
  a seeded sesh/sesh.toml.example, and listed in core-doctor's integrations —
  but tools.zsh never set a HAVE_SESH flag for it the way it does for the
  other detected tools. (Detection itself still worked — the Ctrl-G/prefix + f
  fallback keys off command -v sesh, and core-doctor already probes sesh
  the same way.) tools.zsh now sets
  HAVE_SESH (like HAVE_GUM, no _core_wired arm — sesh registers no persistent
  shell hook, so presence ≈ wired), and PORTING-MATRIX.md gains a sesh row +
  footnote documenting the go install github.com/joshmedeski/sesh/v2@latest build
  path (the v2 module path; go is already a pinned mise runtime) for the
  distros that don't package it. No core.manifest change — the .example is
  already listed.
• RELEASE-RUNBOOK.md — the step-by-step, copy-paste recipe for cutting a release
  (Core, the OS-repo fan-out rollout, and htpx), plus a "dry-run a new cross-repo
  workflow before relying on it" habit and a troubleshooting table. Complements
  RELEASE-STRATEGY.md (the policy); cross-linked from it and CLAUDE.md.

Changed

• nvim: disable <LeftDrag> and <LeftRelease> in all modes unconditionally.
  Previously these were suppressed only when inside a $TMUX session, in Normal and
  Visual modes. They are now <Nop> in Normal, Insert, and Visual modes regardless of
  environment, eliminating accidental mouse-drag selections during terminal use.

• bootstrap-test.yml retries the per-distro prep step (up to 5x with backoff).
  The reusable links-only job ran the dep install once; a transient distro-mirror
  timeout (notably openSUSE Tumbleweed's OSS CDN) then redded the job — and every Core
  fan-out PR — on a network blip. The retry is fleet-wide (one place, every caller);
  a genuinely broken prep still fails loud after the attempts are exhausted.