Fail fast when the daemon isn't running instead of waiting the full 20s RPC connect timeout #178

When no daemon is listening at --pkcRpcUrl, every command that connects to it waits the full 20 seconds before reporting the daemon isn't running, even though the connection is refused right away:

$ time bitsocial community list --pkcRpcUrl ws://127.0.0.1:1
Error: Could not connect to the daemon at ws://127.0.0.1:1/. Is it running? Start it with: bitsocial daemon
real    0m20.569s

This affects every caller of BaseCommand._connectToPkcRpc (src/cli/base-command.ts): community list/get/create/edit/delete/start/stop/export, and the in-use check in challenge remove and page-sort remove (#176, #177).

Cause

pkc-js reports the refused connection almost immediately and then retries every second, until its own ERR_FAILED_TO_OPEN_CONNECTION_TO_RPC at about 20s:

197 ms   error  connect ECONNREFUSED 127.0.0.1:1
1199 ms  error  connect ECONNREFUSED 127.0.0.1:1
...
4205 ms  error  connect ECONNREFUSED 127.0.0.1:1
20207 ms error  ERR_FAILED_TO_OPEN_CONNECTION_TO_RPC

_connectToPkcRpc collects those error events but only looks at them when its 20s timer fires. It only resolves early on communitieschange.

Proposal

• Fail fast when the connection is refused: reject once ECONNREFUSED keeps repeating for a short grace period (about 2s). The grace period covers a daemon that is still starting, since it binds the RPC port partway through startup. Then throw the existing "Could not connect to the daemon… Is it running?" message.
• Keep the 20s timeout for everything else: a host that accepts the connection but doesn't answer, slow remote daemons, and ERR_RPC_AUTH_REQUIRED, which is already rethrown as is.
• Destroy the pkc instance on rejection so its retry loop doesn't keep the process alive.

Done when

• A command pointed at a closed local port fails in about 2s instead of 20s, with the same message.
• A test covers it (for example, community list --pkcRpcUrl ws://127.0.0.1:1 finishes well under 20s), plus one showing that a daemon starting within the grace period still connects.
• The "refuses to remove when the daemon cannot be reached" tests in test/cli/challenge.test.ts and test/cli/page-sort.test.ts (about 20s each today) speed up accordingly.