v0.3.7: further ergonomic improvements

v0.3.7 — Contract And Recovery Polish

Improvements

Run and help contracts are tighter and more consistent — runs show and
runs wait now expose a top-level data.status alias for machine consumers
while preserving data.run.status, root help no longer overpromises --session
support for execution-id run commands, and history --help now documents
selector shortcuts such as @latest, @last-error, and @last-success.

Recovery paths are more explicit and less stateful — Foreground exec now
reports when it had to replace a dead or stale kernel and makes the resulting
state loss explicit in both human and JSON output. Stopping the current session
also clears the remembered-session preference so later bare exec does not
silently revive a stopped named session.

Dependency repair is now shell-first instead of session-mutation-first —
Missing live-session modules now point first to uv pip install --python ...
for the selected interpreter, startup and doctor no longer try to install
ipykernel automatically, and missing-startup guidance now tells the user to
install it explicitly and restart with --fresh.

Inspection and exec output are more informative — inspect now supports
safe dotted and constant-subscript references such as df.a and
payload['items'][0], nested previews preserve JSON-like structure more
faithfully, runs show and runs wait preserve multiline stdout and stderr in
human output, and file execution now reports compact namespace changes when a
script completes without stdout, stderr, or a final expression result.

Quiet-mode behavior is clearer — --quiet now suppresses non-essential
success-path chatter without hiding primary output or failure recovery guidance,
while --no-suggestions suppresses only the Next: block.