feat: Add command for uploading frontend sourcemaps [OB-143]

[devin-ai-integration]

Add sourcemaps command for uploading frontend sourcemaps

This PR adds a new sourcemaps command to the LaunchDarkly CLI for uploading JavaScript sourcemaps to LaunchDarkly for error monitoring. The implementation is based on the existing sourcemap uploader in the observability-sdk repository.

Implementation Details

• Added a new top-level sourcemaps command with an upload subcommand
• Implemented the sourcemap upload functionality from the TypeScript implementation in Go
• Added support for the same parameters as the original implementation:
  • --api-key (required): The LaunchDarkly Observability API key
  • --app-version: The current version of your deploy
  • --path: Sets the directory of where the sourcemaps are (defaults to current directory)
  • --base-path: An optional base path for the uploaded sourcemaps
  • --backend-url: An optional backend url for self-hosted deployments

Features

• Verifies API key validity before attempting uploads
• Recursively finds all .js.map files in the specified directory
• Skips node_modules directories when searching for sourcemaps
• Generates S3 upload URLs for each sourcemap file
• Uploads sourcemaps to LaunchDarkly's servers
• Provides progress feedback during the upload process

Testing

• Verified that the implementation passes all tests in the ldcli repository
• Manually tested the command functionality

Link to Devin run

https://app.devin.ai/sessions/11aee1380731458dacd92573c687372f

Requested by: vkorolik@launchdarkly.com

---

Related Jira issue: O11Y-5: create a ldcli sourcemap uploader command

[devin-ai-integration]

Original prompt from vkorolik@launchdarkly.com:

Repo: launchdarkly/ldcli
Repo: launchdarkly/observability-sdk
File: observability-sdk/sdk/highlight-sourcemap-uploader/src/index.ts

update ldcli to add a new command for uploading frontend sourcemaps to be used with launchdarkly error monitoring. to do this, I essentially want to implement the logic from observability-sdk sourcemap-uploader from index.ts into the CLI.

You only need to look in the following repos: launchdarkly/ldcli, launchdarkly/observability-sdk

[devin-ai-integration]

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[Vadman97]

validating behavior locally

[mike-zorn]

Aside @Vadman97 I made some suggestions that caused code changes. I think it's good to merge, but you'll need to re-test

[Vadman97]

validated latest behavior is correct

[Vadman97]

addressing feedback raised in https://github.com/launchdarkly/observability/pull/71 to make the authentication strategy more robust (forwarding the access token to highlight to perform the authentication there. let me know if there are any concerns with this approach.

[Vadman97]

validated with changes from https://github.com/launchdarkly/observability/pull/71