fix(frank-archon): raise the ttm knob from a root ExecStartPre — User=dank cannot write it

a9da65e put the raise inside the serve script, which runs as `User=dank`: the
knob is root-owned 0644, so `-w` is false and the write silently failed — the
gate printed its refusal on a cap it had just failed to move. The privileged
path is systemd's `+` prefix: `ExecStartPre=+scripts/ttm-preflight.sh --raise`
runs as root even under `User=`, before ExecStart, so `Restart=always` can
never outrun it. The lib is now also executable (`--raise` sources the env file
and verifies), and keeps a `sudo -n` fallback for a human running the gate from
a shell.

Seam: the refusal cases run with a PATH that has `cat`+`bash` and NO `sudo`
(root writes a 444 file, so a passwordless dev box would have tested nothing),
and both now assert the gate's own exit 1, not merely non-zero. New seam covers
the unit line and the `--raise` entry point end to end (writable knob -> raised,
no args -> usage exit 2).

scripts/frank-archon.service

@@ -35,6 +35,13 @@ Group=dank
 LimitMEMLOCK=infinity
 Environment="FRANK_ARCHON_ENV_FILE=/home/dank/serverAppConfigs/scripts/frank-archon.env"
 ExecStart=/home/dank/serverAppConfigs/scripts/serve-frank-archon.sh
+# The `+` prefix runs this as root even though the service is User=dank — the
+# ttm pages cap is a root-owned knob and the pinned-RAM ledger (~147 GiB) is
+# unusable below it. After a reboot the knob is back at its default (half of
+# RAM), so the raise must be part of the start, not a note in a runbook: the
+# 2026-10-12 power failure reset it and the endpoint refused to boot 6,919
+# times. The serve script re-verifies the cap after this hook.
+ExecStartPre=+/home/dank/serverAppConfigs/scripts/ttm-preflight.sh --raise
 # systemd stop: wait alone cannot stop the container child; stop it
 # explicitly. No graceful drain contract is claimed (the OpenAI front end
 # holds no queue to drain — in-flight decodes are lost, which a stop

scripts/ttm-preflight.sh

@@ -42,15 +42,24 @@ ttm_cap_mib() {
     echo "${cur:-0}"
 }
 
-# Writes $1 MiB (as 4 KiB pages) into every writable knob present. Failures are
+# Writes $1 MiB (as 4 KiB pages) into every knob present. Failures are
 # swallowed: the caller re-reads the cap, and a write the kernel refused shows
 # up there (ttm refuses a limit below the pages it has already pinned).
+#
+# PRIVILEGE, measured the hard way: the knob is root-owned 0644 and the service
+# process runs as User=dank, so `-w` is FALSE there and a plain echo fails. The
+# canonical privileged path is the unit's ExecStartPre with the `+` prefix
+# (systemd runs it as root even under User=); `sudo -n` is the fallback for a
+# human running the gate from a shell (passwordless sudo on both hosts).
 ttm_raise_cap() {
     local pages=$(( $1 * 256 )) p
     for p in "$FRANK_ARCHON_TTM_SYS_DIR/pages_limit" \
              "$FRANK_ARCHON_TTM_SYS_DIR/pages_max"; do
+        [ -e "$p" ] || continue
         if [ -w "$p" ]; then
             echo "$pages" > "$p" 2>/dev/null || true
+        elif command -v sudo >/dev/null 2>&1; then
+            sudo -n sh -c "echo $pages > '$p'" >/dev/null 2>&1 || true
         fi
     done
 }
@@ -74,3 +83,22 @@ ttm_ensure_cap() {
     fi
     echo "frank-archon: ttm pages cap ${cap} MiB clears the pinned-ledger floor $FRANK_ARCHON_TTM_MIN_MIB" >&2
 }
+
+# Executed (not sourced) it is the privileged pre-start hook: systemd runs this
+# as root from the unit's `ExecStartPre=+…`, where the knob write is legal and
+# the `Restart=always` loop can never outrun it.
+if [ "${BASH_SOURCE[0]}" = "${0}" ]; then
+    set -euo pipefail
+    case "${1:-}" in
+        --raise)
+            TTM_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+            # shellcheck source=/dev/null
+            source "${FRANK_ARCHON_ENV_FILE:-$TTM_DIR/frank-archon.env}"
+            ttm_ensure_cap
+            ;;
+        *)
+            echo "usage: ${0##*/} --raise   (raise the ttm pages cap, then verify)" >&2
+            exit 2
+            ;;
+    esac
+fi