workstation: per-user playwright browser MCP for all users, reproducible from git

Viktor asked that the playwright browser MCP be available for every devvm user
in every directory, with each user running their own server and multiple
concurrent sessions per user.

Before this, playwright was hand-set-up per user (~/.config/systemd/user/
playwright-mcp.service on 8931/8932/8933) and only wizard was actually wired —
emo's and anca's servers ran but their ~/.claude.json had no playwright entry,
so their Claude never connected. None of it was reproducible from git (units,
refresh script, and the Vault snapshot token lived only in user homes), so a
devvm rebuild would silently lose it.

This makes it reproducible and fixes the unwired users:

- roster_engine.py: sticky per-user PLAYWRIGHT_PORT (PLAYWRIGHT_BASE_PORT=8931,
  allocated for every roster user incl. the admin), emitted in the derive JSON.
- scripts/workstation/playwright/: system-level TEMPLATE units
  (playwright-mcp@.service + playwright-snapshot-refresh@.{service,timer},
  User=%i — system manager, so no systemd --user / linger) + the refresh script.
  @playwright/mcp pinned to 0.0.76 (avoids the @latest silent-fleet-roll
  footgun, same rationale as T3_PIN).
- setup-devvm.sh: install the templates + script (9e); stage the chrome-service
  snapshot bearer token from Vault to a root file (8c) — the hourly root
  reconcile has no Vault token, mirrors the Claude OAuth staging in 8a.
- t3-provision-users.sh: install_playwright() (ALL tiers incl. admin) writes
  PLAYWRIGHT_PORT, seeds the token if-absent, wires the user-scope ~/.claude.json
  by running `claude mcp add` AS the user (clobber-proof + if-absent, so it fixes
  existing/new/admin without rewriting a populated config), and enable --now's the
  instances (idempotent, never restarts a running server). Also hardened the
  section-1 *.env scan to skip the new playwright-*.env files (no T3_PORT -> grep
  no-match would abort under set -e -o pipefail).
- Docs: chrome-service-snapshot runbook (new Provisioning section + system-unit
  commands), multi-tenancy.md, and the 2026-06-07 plan Task 2.3.

Supersedes the hand-made per-user --user units (one-time idle-gated migration to
follow on the live host).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

scripts/workstation/setup-devvm.sh

@@ -140,6 +140,16 @@ if command -v vault >/dev/null; then
   else
     log "WARN: secret/workstation codex_shared_auth_json absent -> shared Codex auth not staged"
   fi
+  # 8c) chrome-service snapshot bearer token -> root file the provisioner copies
+  #     per-user (if-absent) to ~/.config/playwright/token, which the per-user
+  #     playwright-snapshot-refresh reads. One token for all users (single shared
+  #     warm profile, by design). 0600: the snapshot it fetches holds cookies.
+  if cs_tok="$(vault kv get -field=api_bearer_token secret/chrome-service 2>/dev/null)"; then
+    install -m 0600 /dev/stdin /etc/t3-serve/chrome-service-token <<<"$cs_tok"
+    log "staged /etc/t3-serve/chrome-service-token (playwright snapshot auth)"
+  else
+    log "WARN: secret/chrome-service api_bearer_token absent -> playwright snapshot refresh will 401"
+  fi
 fi
 
 # 9) service layer: install + enable the machine-wide systemd units (sources in
@@ -177,6 +187,16 @@ for u in t3-serve@.service \
          t3-dispatch.service; do
   install -m 0644 "$SCRIPTS/$u" "/etc/systemd/system/$u"
 done
+# 9e) per-user playwright-mcp browser MCP: system-level TEMPLATE units (one
+#     instance per OS user) + the snapshot-refresh script. Reproducible-from-git
+#     replacement for the hand-made ~/.config/systemd/user/playwright-* units
+#     (no systemd --user / linger needed). Enabled per-user by the provisioner;
+#     PLAYWRIGHT_PORT (roster_engine) + the chrome-service token (8c) feed them.
+install -m 0755 "$HERE/playwright/playwright-snapshot-refresh" /usr/local/bin/playwright-snapshot-refresh
+for u in playwright-mcp@.service playwright-snapshot-refresh@.service playwright-snapshot-refresh@.timer; do
+  install -m 0644 "$HERE/playwright/$u" "/etc/systemd/system/$u"
+done
+log "playwright: template units + snapshot-refresh script installed (per-user enable in provisioner)"
 systemctl daemon-reload
 systemctl enable --now t3-dispatch.service \
   t3-autoupdate.timer t3-backup-state.timer t3-provision-users.timer >/dev/null 2>&1 || \