fix(ai-vterm): direction-based display + per-project tmux session names

Two post-ship issues blocked practical use of the new launcher.

The display rule used `display-buffer-in-side-window` with `(dedicated . t)`. Side-window dedication caused `set-window-buffer` to error during `buffer-move` (C-M-arrows), which left a half-finished swap with both sides showing the claude buffer. Then `switch-to-buffer` on a non-claude buffer in that dedicated window split instead of replacing.

I rewrote the rule as `display-buffer-reuse-window -> display-buffer-use-some-window -> display-buffer-in-direction (right)`. The resulting window is ordinary, not dedicated, so swap and replace work normally. I also narrowed `vterm-toggle`'s broad lambda (which matches any vterm-mode buffer) to exclude `claude [` buffers. Otherwise vterm-toggle's `:defer` made it install last and capture our buffers first with its own bottom-split + dedicated treatment.

The tmux side: vterm's auto-launch hook ran a bare `tmux\n`, so each session got an auto-named one. After an Emacs crash the tmux session would survive but I couldn't find it. A second F9 just spawned another. The launcher now sends `tmux new-session -A -s <basename> -c <dir> '<claude>; exec bash'`. The `-A` reattaches to a same-named session if it already exists. The `exec bash` keeps the tmux window alive if claude itself exits. A `cj/--ai-vterm-suppress-tmux` flag tells the existing vterm hook to skip its bare tmux step so the named launch runs instead.

11 new tests across 2 files cover the session-name and launch-command helpers. I updated tests for show-or-create and the display rule. All 34 ai-vterm tests are green.

0 files changed, 0 insertions, 0 deletions