feat(setup): paint card and log bodies in brand cyan

Adds a `brandBody` helper in setup/lib/theme.ts that wraps prose in
brand cyan (#2BB7CE), with the same TTY/NO_COLOR/truecolor gating used
by `brand`/`brandBold`/`brandChip`. The helper splits multi-line input
and colors each line independently so the SGR sequence doesn't bleed
across clack's gutter prefix.

Routing:
  - `note()` (the un-dim card wrapper from #2095) now passes
    `brandBody` as its `format` callback, so card bodies render
    cyan line-by-line.
  - Every prose `p.log.{message,info,success,step,warn}` call in the
    setup flow wraps its body argument in `brandBody`. Calls whose
    body is explicitly `k.dim(...)` (failure transcript tails, log
    paths, claude-assist response previews) are left alone — those
    are the "preview/debug" cases the dim-policy comment in
    theme.ts already carves out.
  - Spinner-finish lines in windowed-runner / claude-assist color
    only the message portion; the `(5s)` elapsed suffix stays dim.

Brand cyan accents (chips, wordmark, inline emphasis) are unchanged.
This PR only adds the body color.

A follow-up will add OSC 11 dark/light detection so light-mode
terminals get a brand blue (#2b6fdc) variant — opt-in upgrade with
no regression for the dark-mode default.

setup/channels/discord.ts

@@ -31,7 +31,7 @@ import { brightSelect } from '../lib/bright-select.js';
 import { confirmThenOpen } from '../lib/browser.js';
 import { askOperatorRole } from '../lib/role-prompt.js';
 import { ensureAnswer, fail, runQuietChild } from '../lib/runner.js';
-import { note } from '../lib/theme.js';
+import { brandBody, note } from '../lib/theme.js';
 
 const DEFAULT_AGENT_NAME = 'Nano';
 const DISCORD_API = 'https://discord.com/api/v10';
@@ -386,7 +386,7 @@ async function resolveOwnerUserId(
     }
   } else {
     p.log.info(
-      "Your bot is owned by a Developer Team, so we need your Discord user ID directly.",
+      brandBody("Your bot is owned by a Developer Team, so we need your Discord user ID directly."),
     );
   }
   return await promptForUserIdWithDevMode();

setup/channels/whatsapp.ts

@@ -46,7 +46,7 @@ import {
   writeStepEntry,
 } from '../lib/runner.js';
 import { askOperatorRole } from '../lib/role-prompt.js';
-import { brandBold, note } from '../lib/theme.js';
+import { brandBody, brandBold, note } from '../lib/theme.js';
 
 const DEFAULT_AGENT_NAME = 'Nano';
 const AUTH_CREDS_PATH = path.join(process.cwd(), 'store', 'auth', 'creds.json');
@@ -267,7 +267,7 @@ async function runWhatsAppAuth(
           if (spinnerActive) {
             stopSpinner('WhatsApp linked.');
           } else {
-            p.log.success('WhatsApp linked.');
+            p.log.success(brandBody('WhatsApp linked.'));
           }
         } else if (status === 'failed') {
           if (qrLinesPrinted > 0) {