feat: Add centralized logging system with @link-stack/logger package

- Create new @link-stack/logger package wrapping Pino for structured logging
- Replace all console.log/error/warn statements across the monorepo
- Configure environment-aware logging (pretty-print in dev, JSON in prod)
- Add automatic redaction of sensitive fields (passwords, tokens, etc.)
- Remove dead commented-out logger file from bridge-worker
- Follow Pino's standard argument order (context object first, message second)
- Support log levels via LOG_LEVEL environment variable
- Export TypeScript types for better IDE support

This provides consistent, structured logging across all applications
and packages, making debugging easier and production logs more parseable.

packages/logger/src/config.ts

@@ -0,0 +1,56 @@
+import type { LoggerOptions } from 'pino';
+
+export const getLogLevel = (): string => {
+  return process.env.LOG_LEVEL || (process.env.NODE_ENV === 'production' ? 'info' : 'debug');
+};
+
+export const getPinoConfig = (): LoggerOptions => {
+  const isDevelopment = process.env.NODE_ENV !== 'production';
+  
+  const baseConfig: LoggerOptions = {
+    level: getLogLevel(),
+    formatters: {
+      level: (label) => {
+        return { level: label.toUpperCase() };
+      },
+    },
+    timestamp: () => `,"timestamp":"${new Date(Date.now()).toISOString()}"`,
+    redact: {
+      paths: [
+        'password',
+        'token',
+        'secret',
+        'api_key',
+        'apiKey',
+        'authorization',
+        'cookie',
+        '*.password',
+        '*.token',
+        '*.secret',
+        '*.api_key',
+        '*.apiKey',
+      ],
+      censor: '[REDACTED]',
+    },
+  };
+
+  if (isDevelopment) {
+    // In development, use pretty printing for better readability
+    return {
+      ...baseConfig,
+      transport: {
+        target: 'pino-pretty',
+        options: {
+          colorize: true,
+          translateTime: 'SYS:standard',
+          ignore: 'pid,hostname',
+          singleLine: false,
+          messageFormat: '{msg}',
+        },
+      },
+    };
+  }
+
+  // In production, use JSON for structured logging
+  return baseConfig;
+};