refactor(setup): drop CLI-bonus wiring from init-first-agent

init-first-agent used to double-wire the CLI channel to every new DM
agent as a convenience for `pnpm run chat`, gated by --no-cli-bonus.
With the /new-setup-2 flow gone and a dedicated scratch CLI agent
created earlier in setup:auto, that bonus just stomps on CLI routing
the user already set up. Remove the CLI_CHANNEL/CLI_PLATFORM_ID
constants, ensureCliMessagingGroup, the --no-cli-bonus flag, and the
cli-bonus wiring block.

Pass the paired user's identity through to the welcome delivery so
the sender resolver sees the real owner (e.g. telegram:<id>) instead
of cli:local. Extend the CLI channel's admin-transport payload to
accept optional sender/senderId overrides — falls back to the old
cli/cli:local defaults when omitted, so existing callers are unchanged.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/channels/cli.ts

@@ -183,6 +183,8 @@ function createAdapter(): ChannelAdapter {
       text?: unknown;
       to?: unknown;
       reply_to?: unknown;
+      sender?: unknown;
+      senderId?: unknown;
     };
     try {
       payload = JSON.parse(line);
@@ -209,8 +211,8 @@ function createAdapter(): ChannelAdapter {
           timestamp: new Date().toISOString(),
           content: JSON.stringify({
             text: payload.text,
-            sender: 'cli',
-            senderId: `cli:${PLATFORM_ID}`,
+            sender: typeof payload.sender === 'string' ? payload.sender : 'cli',
+            senderId: typeof payload.senderId === 'string' ? payload.senderId : `cli:${PLATFORM_ID}`,
           }),
         },
         replyTo: replyTo ?? undefined,