fix: transport escalation exempts log reads, get_entity accepts slug alias, add restart_service + push_file tools

P0: Transport escalation in classifyAndGate (server.go:745) now exempts
    log-inspection commands (tail/head/cat/journalctl on *.log or /logs/)
    from the /opt//etc//var/lib/ gating on LXC targets. Fixes the
    'tail -3 /opt/seanime/data/logs/seanime.log queued for approval' bug.

P1: queryEntity returns actionable error when slug_or_id param is empty
    ('slug_or_id is required') instead of silent 'entity not found: '.

P2: Added slugArg() helper (server.go) so get_entity, get_relations,
    get_blast_radius, and explain accept 'slug' as an alias for their
    declared param name. Solves the discoverability inconsistency where
    every tool used a different param name for the same concept.

P3: Two new MCP tools:
    - restart_service(target, service) — systemctl restart wrapper,
      correctly classified config_mutation (requires approval)
    - push_file(target, source_path, dest_path, backup=true) — pct push
      from Proxmox host into LXC, with optional backup. Classified
      config_mutation. LXC-only for now.

P4: Updated homelab-lxc-ops skill with MCP tools preference table.

Plus: Wails desktop build now uses build-tag approach for frontend embed
      (assets_embed.go + assets_stub.go), so go build ./... works on
      clean checkout without the frontend built first.

Version: 0.31.0 → 0.32.0

internal/mcp/server.go

@@ -300,6 +300,22 @@ func argsMap(req *mcp.CallToolRequest) map[string]any {
 	return m
 }
 
+// slugArg returns the first non-empty string value among the given keys.
+// Tools historically used inconsistent param names for "the entity slug"
+// (slug_or_id, entity_id, service_slug, lxc_slug, target). This lets a single
+// handler accept any of them, so an agent guessing "slug" still works.
+func slugArg(m map[string]any, keys ...string) string {
+	if m == nil {
+		return ""
+	}
+	for _, k := range keys {
+		if s, ok := m[k].(string); ok && strings.TrimSpace(s) != "" {
+			return strings.TrimSpace(s)
+		}
+	}
+	return ""
+}
+
 func getFloat(m map[string]any, key string, def float64) float64 {
 	if m == nil {
 		return def
@@ -353,6 +369,9 @@ func jsonErr(format string, args ...any) []byte {
 }
 
 func queryEntity(ctx context.Context, pool *db.Pool, idOrSlug string) *mcp.CallToolResult {
+	if strings.TrimSpace(idOrSlug) == "" {
+		return textResult("slug_or_id is required — expected an entity slug (e.g. lxc:seanime) or UUID")
+	}
 	var id uuid.UUID
 	if u, err := uuid.Parse(idOrSlug); err == nil {
 		id = u
@@ -742,9 +761,15 @@ func classifyAndGate(ctx context.Context, pool *db.Pool, agentID, targetID uuid.
 	// the same command locally on the Proxmox host via pct exec.
 	// Caught live: "cat /etc/hostname" on lxc:dns queued as config_mutation
 	// while "pct exec 107 -- cat /etc/hostname" on host:hubris auto-ran.
+	//
+	// EXEMPTION: tail/head/cat/less/journalctl on log files (*.log, */logs/*)
+	// are always read-only — caught live 2026-08-15 session f6a7d4e:
+	// "tail -3 /opt/seanime/data/logs/seanime.log" on lxc:seanime was gated.
 	if riskClass == policy.RiskReadOnly && strings.HasPrefix(targetSlug, "lxc:") {
-		if strings.Contains(command, "/opt/") || strings.Contains(command, "/etc/") || strings.Contains(command, "/var/lib/") {
-			riskClass = policy.RiskConfigMutation
+		if !isLogInspectionRead(command) {
+			if strings.Contains(command, "/opt/") || strings.Contains(command, "/etc/") || strings.Contains(command, "/var/lib/") {
+				riskClass = policy.RiskConfigMutation
+			}
 		}
 	}
 
@@ -1134,6 +1159,22 @@ func hostLxcCommand(cmd string) (string, bool) {
 	return first, hostLxcCommands[first]
 }
 
+// isLogInspectionRead returns true if the command is a safe read-only operation
+// on a log file — tail, head, cat, less, or journalctl with a .log or /logs/ path.
+// Used by the transport-aware escalation check to avoid gating the most common
+// debugging action (e.g. "tail -3 /opt/seanime/data/logs/seanime.log" on lxc:seanime).
+func isLogInspectionRead(cmd string) bool {
+	trimmed := strings.TrimSpace(cmd)
+	for _, prefix := range []string{"tail ", "head ", "cat ", "less ", "journalctl "} {
+		if strings.HasPrefix(trimmed, prefix) {
+			if strings.Contains(trimmed, ".log") || strings.Contains(trimmed, "/logs/") {
+				return true
+			}
+		}
+	}
+	return false
+}
+
 // validateCommandSyntax checks for common LLM-generated bash errors that always
 // fail at the shell. Returns an error message or "" if the command looks valid.
 func validateCommandSyntax(cmd string) string {