docs: add changelog for cli@0.21.0

[augmentmoogi]

Add changelog entry for CLI version 0.21.0 to CHANGELOG.md.

New Features

• Automatic marketplace updates — installed plugin marketplaces now update in the background, with prompts for workspace-recommended marketplaces
• MCP OAuth paste fallback — allow pasting the auth code during MCP OAuth flows for remote SSH environments

Improvements

• Add timeouts and graceful fail-safes for cloud agent interactive tools in headless environments
• Improve granular status reporting during cloud agent execution
• Keep chat transcript visible when transitioning from plan mode to implementation
• Optimize plan mode sub-agent by eliminating redundant output operations
• Ensure auggie command list consistently displays help text
• Update startup login message for new users
• Fix terminal bell to ring when the agent awaits user input

Bug Fixes

• Fix cloud agent queue not pausing correctly when interrupted mid-execution
• Fall back to native Git approach for indexing extremely large repositories
• Fix custom plugin commands not being invoked via auggie command
• Fix "Indexing complete" displaying multiple times at startup
• Fix CLI initialization hang when connecting to a stuck MCP server

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🤖 This description was generated automatically. Please react with 👍 if it's helpful or 👎 if it needs improvement.

[augment-app-staging]

Code Review Triage 🛡️ · Low Risk

Recommendation: ✅ Approve — Low-Risk Change

Justification

This PR only adds a new changelog entry to CHANGELOG.md for cli@0.21.0. It is a documentation-only change with no executable code, configuration, infrastructure, or test modifications. The diff is 22 added lines of plain Markdown describing new features, improvements, and bug fixes. There is no risk of runtime behavior change.

If you don't agree with this auto-approval recommendation, please reach out to #feedback-code-review-agent.

[github-actions]

Changelog entry is well-structured and consistent with the existing format. However, several entries in the 0.21.0 section appear to significantly overlap with features already documented in 0.20.0, which could confuse readers about what's actually new. See inline comments for details.

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🤖 Automated review complete. Please react with 👍 or 👎 on the individual review comments to provide feedback on their usefulness.

[github-actions]

This entry appears to combine two features already documented in 0.20.0:

• Marketplace Auto-Update: "Installed marketplace repos are automatically updated in the background on startup"
• Recommended Marketplaces: "Projects can declare recommended marketplaces in .augment/settings.json that prompt installation on first open"

The 0.21.0 description ("Installed plugin marketplaces are now automatically updated in the background, with a prompt for workspace-recommended marketplaces") reads like the same functionality. If 0.21.0 contains incremental improvements over 0.20.0, consider wording that clarifies what changed (e.g., "Improved marketplace auto-update to...") rather than re-announcing the feature as new.

[github-actions]

This closely mirrors the 0.20.0 entry:

MCP OAuth Paste Mode: When authenticating MCP servers over SSH, you can now paste the auth code or redirect URL directly instead of relying on localhost redirect

If 0.21.0 adds a fallback mechanism on top of the existing paste mode, consider making that distinction clearer. As written, it reads like a re-announcement of the same feature.

[github-actions]

The 0.20.0 changelog already includes:

Notification Bell on Ask-User: Terminal bell now rings when the agent prompts for user input (when notificationMode is set to bell)

The 0.21.0 entry ("Now correctly rings when the agent is waiting for user input") sounds more like a bug fix for the 0.20.0 feature. Consider moving this to the Bug Fixes section if the bell wasn't working correctly before, or clarifying what specifically improved.

[augment-app-staging]

Review completed. No suggestions at this time.

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[augment-app-staging]

Auto-approved: documentation-only changelog addition.