feat(worker): AskUser MCP tool so a running task can ask the user mid-run

A running task can call mcp__claudedo_run__AskUser(question) to block (up to 3
min) on a human answer. PendingQuestionRegistry holds the pending question +
TaskCompletionSource; the tool broadcasts TaskQuestionAsked, awaits the answer
(WorkerHub.AnswerTaskQuestion resolves it), and returns it as the tool result —
or a 'proceed on your judgment' fallback on timeout. The run stays Running
throughout (no status/schema change). ClaudeProcess raises MCP_TOOL_TIMEOUT so
the 60s HTTP-MCP cap doesn't kill the wait; the run MCP is now wired for every
task, not just standalone ones. System prompt updated to reconcile 'unattended'.

src/ClaudeDo.Data/PromptFiles.cs

@@ -105,9 +105,12 @@ public static class PromptFiles
         - Don't introduce injection/XSS/secret-leak issues. Never commit credentials.
 
         ## You are running unattended
-        You run autonomously with no human watching. There is no one to answer mid-task
-        questions, so never stop to ask — make the most reasonable decision, note the
-        assumption, and continue.
+        You run autonomously, usually with no one watching. Default to making the most
+        reasonable decision yourself, noting the assumption, and continuing — do not stop
+        for routine choices. The one exception: at a genuine fork where a wrong guess
+        would be costly or hard to undo (an irreversible action, contradictory
+        requirements), you may call AskUser(question) to ask the user and wait briefly for
+        an answer. If no one responds in time, proceed on your best judgment.
 
         ## When you are blocked
         If something genuinely prevents you from completing part of the task (missing