feat(server): S3 box is for coding — OOM kills the command not the session, no tests from Claude, 4 AI sessions per member

- tool-run (CLAUDE_CODE_SHELL_PREFIX in member panes) runs each command
  Claude runs at oom_score_adj 1000 (session 300, Terminal tab 800,
  dashboard/tmux -100), so an OOM inside the capped unit kills the test
  run and tells Claude why, instead of killing the conversation.
- member-guard.js, a synchronous managed hook for ah-* accounts: denies
  test runners and container commands from Claude's Bash, and refuses
  the prompts of a session started by hand past MAX_AI_SESSIONS.
- ai-procs.js counts a member's top-level AI processes from /proc;
  spawnRun refuses a new pane past the limit (429 ESESSIONLIMIT).
Needs `agenthub server install-system` once, then a restart.

scripts/server/pane-launch.sh

@@ -11,7 +11,7 @@
 #
 # The file is NUL-separated: the number of environment entries, the
 # NAME=value entries, then the argv (none = a login shell). Every pane starts
-# at a lower CPU/IO priority and as the kernel's first OOM pick (see below).
+# at a lower CPU/IO priority, Claude's commands as the kernel's first OOM pick.
 # @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 set -eu
 f=${1:?usage: pane-launch <launch file>}
@@ -24,19 +24,26 @@ for kv in "${parts[@]:1:n}"; do
   export "$kv"
 done
 # A member's pane shares the 4-core box with the dashboard and every other
-# member: its test run, build or dev server must slow down before anything
-# else does, and die first if memory runs out (11-02: 36 sessions plus test
-# runs filled RAM and swap, and the box froze until a hard reset). A member
-# cannot take the nice back (that needs root); oom_score_adj they can lower
-# only to the unit's own -100, and even then the biggest process dies. The unit
-# caps the whole cgroup below RAM (install-system.sh), so the kernel's pick
-# inside it is the biggest pane process, never the dashboard or tmux.
+# member, so it runs at a lower CPU/IO priority (a member cannot take the
+# nice back: that needs root). Memory (11-02: 36 sessions plus test runs
+# filled RAM and swap, and the box froze until a hard reset): the unit caps
+# its cgroup below RAM (install-system.sh), and inside it the kernel kills
+# by oom_score_adj — the dashboard and tmux at the unit's -100, an AI session
+# at 300, a Terminal tab at 800, and every command Claude runs at 1000
+# through CLAUDE_CODE_SHELL_PREFIX=tool-run. So a runaway command dies and
+# the session that holds the conversation is told why; a member who lowers
+# their own value can go no lower than -100.
 renice -n 10 -p $$ >/dev/null 2>&1 || true
 ionice -c 2 -n 7 -p $$ >/dev/null 2>&1 || true
-echo 500 >/proc/self/oom_score_adj 2>/dev/null || true
+TOOL_RUN=/opt/agenthub/libexec/tool-run
+[ -x "$TOOL_RUN" ] && export CLAUDE_CODE_SHELL_PREFIX="${CLAUDE_CODE_SHELL_PREFIX:-$TOOL_RUN}"
 # Vitest ≤ 3 starts one worker per core by default and these override the
 # config; a member may set their own in the pane.
 export VITEST_MAX_THREADS="${VITEST_MAX_THREADS:-2}" VITEST_MAX_FORKS="${VITEST_MAX_FORKS:-2}"
 argv=("${parts[@]:n+1}")
-if [ ${#argv[@]} -eq 0 ]; then exec -l "${SHELL:-/bin/bash}"; fi
+if [ ${#argv[@]} -eq 0 ]; then
+  echo 800 >/proc/self/oom_score_adj 2>/dev/null || true
+  exec -l "${SHELL:-/bin/bash}"
+fi
+echo 300 >/proc/self/oom_score_adj 2>/dev/null || true
 exec "${argv[@]}"