* perf(kanban): memoize derived board data to stop re-render storms
The board rebuilt the `tasks` array (and `stepOptions`/`sharedProps`) on every
store change, producing fresh object identities that defeated downstream memos
and re-rendered every card on each WebSocket message. Wrap them in useMemo so
the board only re-renders when its inputs actually change.
* perf(session-runtime): bound runtime memory and dedupe git-status compare
Three runtime-store fixes for the crash a heavy rebase triggered:
- Cap shell + terminal output buffers at 2MB (matching the existing process
buffer) so a chatty shell can't grow the store without limit.
- Purge per-session runtime state (messages, turns, shell/process buffers, and
the bySessionId maps) when a session is removed; env-scoped maps are dropped
only once no other session shares the environment.
- Run setGitStatus's deep per-file diff comparison once per update and return
whether anything changed, instead of recomputing it 2-3x. Under a massive
rebase (thousands of files, frequent updates) that comparison was the
dominant CPU cost and drove the render storm.
* refactor(session-runtime): drop now-unused gitStatusWouldMutate
The git-status handler no longer pre-checks for changes (setGitStatus now
returns whether it changed), leaving gitStatusWouldMutate with no callers.
* fix(session-runtime): enforce terminal cap on first and oversized chunks
appendTerminalChunk only evicted when more than one chunk was buffered, so a
single chunk larger than the 2MB cap slipped through untrimmed; the new-terminal
branch also pushed the first chunk without going through the cap at all. Clamp
each chunk to the tail of the cap and route the new-terminal path through
appendTerminalChunk. Addresses CodeRabbit review.
José Almeida
3b2e1396fa