fix(cron): use full prompt mode for isolated cron sessions to include skills (#24944)

Isolated cron sessions (agentTurn) were grouped with subagent sessions
under the "minimal" prompt mode, which causes buildSkillsSection to
return an empty array. This meant <available_skills> was never included
in the system prompt for isolated cron runs.

Subagent sessions legitimately need minimal prompts (reduced context),
but isolated cron sessions are full agent turns that should have access
to all configured skills, matching the behavior of normal chat sessions
and non-isolated cron runs.

Remove isCronSessionKey from the minimal prompt condition so only
subagent sessions use "minimal" mode.

Fixes openclaw#24888

Co-authored-by: Cursor <cursoragent@cursor.com>

src/agents/pi-embedded-runner/run/attempt.ts

@@ -19,7 +19,7 @@ import type {
   PluginHookBeforeAgentStartResult,
   PluginHookBeforePromptBuildResult,
 } from "../../../plugins/types.js";
-import { isCronSessionKey, isSubagentSessionKey } from "../../../routing/session-key.js";
+import { isSubagentSessionKey } from "../../../routing/session-key.js";
 import { resolveSignalReactionLevel } from "../../../signal/reaction-level.js";
 import { resolveTelegramInlineButtonsScope } from "../../../telegram/inline-buttons.js";
 import { resolveTelegramReactionLevel } from "../../../telegram/reaction-level.js";
@@ -494,10 +494,7 @@ export async function runEmbeddedAttempt(
       },
     });
     const isDefaultAgent = sessionAgentId === defaultAgentId;
-    const promptMode =
-      isSubagentSessionKey(params.sessionKey) || isCronSessionKey(params.sessionKey)
-        ? "minimal"
-        : "full";
+    const promptMode = isSubagentSessionKey(params.sessionKey) ? "minimal" : "full";
     const docsPath = await resolveOpenClawDocsPath({
       workspaceDir: effectiveWorkspace,
       argv1: process.argv[1],