docs: add missing README files for modules

modules/logger/README.md

@@ -0,0 +1,19 @@
+# BitGo logger
+
+BitGo logger with sensitive data sanitization. This package provides a logging utility that automatically sanitizes sensitive information before output.
+
+## Installation
+
+```shell
+npm i @bitgo/logger
+```
+
+## Usage
+
+```javascript
+import { logger } from '@bitgo/logger';
+```
+
+## Development
+
+When making changes to `@bitgo/logger`, ensure that the linting, formatting, and testing succeeds when run both within the package and from the root of BitGoJS.

modules/sdk-api/README.md

@@ -0,0 +1,28 @@
+# BitGo sdk-api
+
+REST wrapper for the BitGoJS SDK. This package provides the `BitGoAPI` class used to initialize the SDK and register coin implementations.
+
+## Installation
+
+```shell
+npm i @bitgo/sdk-api
+```
+
+## Usage
+
+`@bitgo/sdk-api` is used as the entry point for accessing individual coin modules:
+
+```javascript
+import { BitGoAPI } from '@bitgo/sdk-api';
+import { Btc } from '@bitgo/sdk-coin-btc';
+
+const sdk = new BitGoAPI();
+
+sdk.register('btc', Btc.createInstance);
+```
+
+## Development
+
+This package provides the REST API layer for communicating with the BitGo platform services. It handles authentication, request signing, and session management.
+
+When making changes to `sdk-api`, ensure that the linting, formatting, and testing succeeds when run both within the package and from the root of BitGoJS.

modules/sdk-coin-ethlike/README.md

@@ -0,0 +1,30 @@
+# BitGo sdk-coin-ethlike
+
+SDK coins provide a modular approach to a monolithic architecture. This and all BitGoJS SDK coins allow developers to use only the coins needed for a given project.
+
+## Installation
+
+All coins are loaded traditionally through the `bitgo` package. If you are using coins individually, you will be accessing the coin via the `@bitgo/sdk-api` package.
+
+In your project install both `@bitgo/sdk-api` and `@bitgo/sdk-coin-ethlike`.
+
+```shell
+npm i @bitgo/sdk-api @bitgo/sdk-coin-ethlike
+```
+
+Next, you will be able to initialize an instance of "bitgo" through `@bitgo/sdk-api` instead of `bitgo`.
+
+```javascript
+import { BitGoAPI } from '@bitgo/sdk-api';
+import { EthLikeCoin } from '@bitgo/sdk-coin-ethlike';
+
+const sdk = new BitGoAPI();
+
+sdk.register('ethlike', EthLikeCoin.createInstance);
+```
+
+## Development
+
+Most of the coin implementations are derived from `@bitgo/sdk-core`, `@bitgo/statics`, and coin specific packages. These implementations are used to interact with the BitGo API and BitGo platform services.
+
+You will notice that the basic version of common class extensions have been provided to you and must be resolved before the package build will succeed. Upon initiation of a given SDK coin, you will need to verify that your coin has been included in the root `tsconfig.packages.json` and that the linting, formatting, and testing succeeds when run both within the coin and from the root of BitGoJS.

modules/sdk-coin-flrp/README.md

@@ -0,0 +1,30 @@
+# BitGo sdk-coin-flrp
+
+SDK coins provide a modular approach to a monolithic architecture. This and all BitGoJS SDK coins allow developers to use only the coins needed for a given project.
+
+## Installation
+
+All coins are loaded traditionally through the `bitgo` package. If you are using coins individually, you will be accessing the coin via the `@bitgo/sdk-api` package.
+
+In your project install both `@bitgo/sdk-api` and `@bitgo/sdk-coin-flrp`.
+
+```shell
+npm i @bitgo/sdk-api @bitgo/sdk-coin-flrp
+```
+
+Next, you will be able to initialize an instance of "bitgo" through `@bitgo/sdk-api` instead of `bitgo`.
+
+```javascript
+import { BitGoAPI } from '@bitgo/sdk-api';
+import { Flrp } from '@bitgo/sdk-coin-flrp';
+
+const sdk = new BitGoAPI();
+
+sdk.register('flrp', Flrp.createInstance);
+```
+
+## Development
+
+Most of the coin implementations are derived from `@bitgo/sdk-core`, `@bitgo/statics`, and coin specific packages. These implementations are used to interact with the BitGo API and BitGo platform services.
+
+You will notice that the basic version of common class extensions have been provided to you and must be resolved before the package build will succeed. Upon initiation of a given SDK coin, you will need to verify that your coin has been included in the root `tsconfig.packages.json` and that the linting, formatting, and testing succeeds when run both within the coin and from the root of BitGoJS.

modules/sdk-core/README.md

@@ -0,0 +1,30 @@
+# BitGo sdk-core
+
+Core library functions for the BitGoJS SDK. This package provides the base classes, interfaces, and shared functionality used across all BitGoJS coin implementations.
+
+## Installation
+
+```shell
+npm i @bitgo/sdk-core
+```
+
+## Usage
+
+```javascript
+import { BaseCoin, BitGoBase, common } from '@bitgo/sdk-core';
+```
+
+## Development
+
+`@bitgo/sdk-core` provides the foundational classes and interfaces that coin-specific packages extend. It includes:
+
+- Base coin class definitions
+- Transaction building interfaces
+- Wallet management utilities
+- Cryptographic primitives
+- TSS (Threshold Signature Scheme) support
+- MPC (Multi-Party Computation) utilities
+- Common error types
+- API interaction layer
+
+When making changes to `sdk-core`, ensure that the linting, formatting, and testing succeeds when run both within the package and from the root of BitGoJS.

modules/secp256k1/README.md

@@ -0,0 +1,20 @@
+# BitGo secp256k1
+
+Low-level cryptographic methods used in BitGo packages for the secp256k1 curve. This package provides ECC (Elliptic Curve Cryptography), BIP32, ECPair, and MuSig2 functionality.
+
+## Installation
+
+```shell
+npm i @bitgo/secp256k1
+```
+
+## Features
+
+- secp256k1 elliptic curve operations via `@noble/secp256k1`
+- BIP32 HD key derivation
+- ECPair key management
+- MuSig2 multi-signature support
+
+## Development
+
+When making changes to `@bitgo/secp256k1`, ensure that the linting, formatting, and testing succeeds when run both within the package and from the root of BitGoJS.

modules/sjcl/README.md

@@ -0,0 +1,13 @@
+# BitGo sjcl
+
+BitGo fork of the [Stanford Javascript Crypto Library](https://github.com/nicerobot/sjcl). This package provides cryptographic primitives used internally by the BitGoJS SDK.
+
+## Installation
+
+```shell
+npm i @bitgo/sjcl
+```
+
+## License
+
+BSD-2-Clause OR GPL-2.0-only