FileBrowser is published only after its default login is checked (R-1126); the memory refusal says what to do (R-1125)

R-1126 (D11 = A): FileBrowser starts off traefik-public, on its own network felhom-filebrowser; the controller joins it
there, checks this run's default login, and only then puts FileBrowser on traefik-public (files.<domain> served).
FileBrowser's own admin-password setting re-applies at every start (1.5.6 cmd/user.go:50-57, measured on 9202), so it
cannot carry the box's password without overwriting the household's own. Tests red-proved.
R-1125 (D10 = A): err.stacks.not_enough_memory says the memory is held by the installed apps and to remove one or use
a machine with more memory (HU + EN, reworded on purpose). TestR1125_NotEnoughMemorySaysWhatToDo, red-proved.

Claude-Session: https://claude.ai/code/session_0159rPz1ZhFKsS53msqPYxtS

controller/internal/stacks/filebrowser_gate.go

@@ -0,0 +1,104 @@
+package stacks
+
+import (
+	"strings"
+
+	"gitea.dooplex.hu/admin/felhom-controller/internal/dockerexec"
+	"gitea.dooplex.hu/admin/felhom-controller/internal/infra"
+)
+
+// R-1126 (operator decision D11 = A, 2026-10-17): FileBrowser is never reachable from outside on its default password.
+//
+// WHY THIS SHAPE. The tunnel runs before the claim (the claim mail links https://felhom.<domain>), and files.<domain> is
+// published through it. A new FileBrowser database starts on admin/admin. FileBrowser's own admin-password setting
+// (config `auth.adminPassword` / env FILEBROWSER_ADMIN_PASSWORD) is RE-APPLIED AT EVERY START (gtstef/filebrowser
+// 1.5.6-stable backend/cmd/user.go:50-57, called from cmd/root.go:144 each start) — measured on scratch 9202: a password
+// the household set in FileBrowser was replaced at the next restart. So the box cannot hand FileBrowser its password up
+// front without overwriting the household's own (R-513's reason, re-proven). Instead FileBrowser starts OFF the
+// traefik-public network (infra.RenderFileBrowserCompose) and the box joins it there only after it has checked THIS run:
+// the default login refused, or replaced and verified (EnsureFileBrowserAdminPassword sets fbProbedRun). A re-created
+// container — the only way a new database appears — always starts unreachable from outside, whoever re-created it.
+// Pinned by TestFileBrowserGate_*.
+
+// fbNetOn reports whether container is on network (test seam: fbNetOnFn; a test FileBrowser and no seam → false).
+func (m *Manager) fbNetOn(container, network string) bool {
+	if m.fbNetOnFn != nil {
+		return m.fbNetOnFn(container, network)
+	}
+	if m.fbHTTP != nil || m.fbBaseURL != "" {
+		return false
+	}
+	return containerOnNetwork(container, network)
+}
+
+// fbNetConnect attaches container to network (test seam: fbNetConnectFn; a test FileBrowser and no seam → no-op).
+func (m *Manager) fbNetConnect(container, network string) error {
+	if m.fbNetConnectFn != nil {
+		return m.fbNetConnectFn(container, network)
+	}
+	if m.fbHTTP != nil || m.fbBaseURL != "" {
+		return nil
+	}
+	out, err := dockerexec.Command("docker", "network", "connect", network, container).CombinedOutput()
+	if err != nil && !strings.Contains(string(out), "already exists") {
+		return &netConnectError{out: strings.TrimSpace(string(out)), err: err}
+	}
+	return nil
+}
+
+type netConnectError struct {
+	out string
+	err error
+}
+
+func (e *netConnectError) Error() string { return e.out + ": " + e.err.Error() }
+
+// joinFileBrowserNetwork puts the controller on FileBrowser's own network, so the default-login check reaches it before
+// FileBrowser is public. Missing network (FileBrowser not deployed yet) → nothing, the next round tries again.
+func (m *Manager) joinFileBrowserNetwork() {
+	if m.fbNetOn(controllerContainer, infra.FileBrowserNetwork) {
+		return
+	}
+	if err := m.fbNetConnect(controllerContainer, infra.FileBrowserNetwork); err != nil {
+		if m.isDebug() {
+			m.logger.Printf("[DEBUG] [infra] filebrowser: controller not joined to %s yet: %v", infra.FileBrowserNetwork, err)
+		}
+		return
+	}
+	m.logger.Printf("[INFO] [infra] connected %s to %s (the FileBrowser default-login check, R-1126)", controllerContainer, infra.FileBrowserNetwork)
+}
+
+// ensureFileBrowserPublic joins FileBrowser to traefik-public only when THIS run was checked and its default login is
+// refused. Anything less — the run unknown, not checked yet, the check failed — leaves it unreachable from outside.
+func (m *Manager) ensureFileBrowserPublic() {
+	run := m.fbStartedAt()
+	if run == "" || run != m.fbProbedRun {
+		return
+	}
+	if m.fbNetOn(fileBrowserContainer, traefikNetwork) {
+		return
+	}
+	if err := m.fbNetConnect(fileBrowserContainer, traefikNetwork); err != nil {
+		m.logger.Printf("[WARN] [infra] filebrowser: could not join %s (files.<domain> stays unreachable): %v", traefikNetwork, err)
+		return
+	}
+	m.logger.Printf("[INFO] [infra] filebrowser: default login refused for this run — joined %s, files.<domain> served (R-1126)", traefikNetwork)
+}
+
+// EnsureFileBrowserGate is the whole check outside the base-stack round — called after web.SyncFileBrowserMounts
+// re-creates FileBrowser, so a household's storage change does not leave the file browser offline until the next round.
+func (m *Manager) EnsureFileBrowserGate() {
+	m.infraMu.Lock()
+	defer m.infraMu.Unlock()
+	m.fileBrowserGateLocked()
+}
+
+// fileBrowserGateLocked runs join → check → publish. The caller holds infraMu.
+func (m *Manager) fileBrowserGateLocked() {
+	m.joinFileBrowserNetwork()
+	if err := m.EnsureFileBrowserAdminPassword(); err != nil {
+		// R-513: retried every round until decided. Logged, never fatal to the base stack.
+		m.logger.Printf("[WARN] [infra] %v", err)
+	}
+	m.ensureFileBrowserPublic()
+}