TypeScript SDK: allow replacing the logger with setGlobalLogger

[mausworks]

Description of Changes

The TypeScript SDK's log output always goes to console.log with %c styling. Only the level can be configured (setGlobalLogLevel), so there's no way to:

• forward SDK logs to an app's own logger or error reporting, or
• get readable output where %c styling isn't supported. In React Native, for example, every line shows the raw %c markers and CSS strings.

This adds a pluggable sink next to the existing level setting:

import { setGlobalLogger, consoleLogger, type Logger } from 'spacetimedb';

setGlobalLogger((level, message, ...args) => {
  console[level === 'trace' ? 'debug' : level](`[stdb] ${message}`, ...args);
});

setGlobalLogger(consoleLogger); // back to the default

• Logger: (level, message, ...args) => void. It's only called for logs that pass the global log level, with lazy messages and arguments already resolved.
• setGlobalLogger and getGlobalLogger: replace or read the current sink, mirroring setGlobalLogLevel and getGlobalLogLevel.
• consoleLogger: the existing styled console.log output, unchanged and still the default.

API and ABI breaking changes

None. This only adds exports, and the default output is unchanged.

Rollback safety impact

n/a

Expected complexity level and risk

1. It's a small, client-only change in src/sdk/logger.ts.

Testing

• Added tests/logger.test.ts cases:
  • a custom logger receives resolved logs instead of the console;
  • it still respects the global log level, and lazy messages aren't evaluated when filtered out;
  • consoleLogger restores the default output.
• vitest run: all 417 tests pass. Locally, server_test_utils_wasm*.test.ts can't load because the portable datastore WASM build is missing; that's unrelated to this change.
• ESLint didn't run locally because the root dependencies weren't installed, so it relies on CI.

🤖 Generated with Claude Code

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[mausworks]

Confirmed working great in my expo project with a plain logger:

setGlobalLogger((level, message, ...args) => {
  console[level](message, ...args);
});