Add browser refs and command input protocol

[glittercowboy]

Summary

• Adds browserRefs relay payloads for rendered ref overlays.
• Adds browser user input kind constants for navigation, history, reload, ref actions, viewport, and device commands.
• Documents the browserRefs message and validates decoding behavior.

Verification

• go test ./...

Downstream

• Daemon and cloud-app consume this module version for browser refs and command input kinds.

Summary by CodeRabbit

New Features

• Added capability to capture and track visible interactive browser references, including their position and size information
• Expanded browser input actions to include navigation controls (back, forward, reload), viewport and device configuration, and interactive element reference actions

Tests

• Added comprehensive test coverage for the new browser references feature, validating serialization and compatibility

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: cc1ac932-adac-4e1a-bde2-a936e6d08ec8

📥 Commits

Reviewing files that changed from the base of the PR and between a4328b6 and aee1274.

📒 Files selected for processing (4)

• PROTOCOL.md
• envelope.go
• messages.go
• messages_test.go

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📝 Walkthrough

Walkthrough

This PR adds a new browserRefs protocol message type enabling daemons to transmit visible interactive browser element references with positional metadata to browsers, along with several new browser input kind constants. It includes protocol documentation, Go type definitions, envelope handling, and comprehensive test coverage.

Changes

Cohort / File(s)	Summary
Protocol Documentation PROTOCOL.md	Adds browserRefs message type specification to the Visual State protocol with fields for browser/session/channel identifiers, version, refs array with positional data, and timestamp.
Message Type Implementation envelope.go, messages.go	Implements MsgTypeBrowserRefs constant, defines BrowserRefs and BrowserRef structs, adds message type routing in envelope's payload switch, and introduces new BrowserInputKind* constants for navigation, viewport, and device emulation actions.
Test Coverage messages_test.go	Adds round-trip serialization tests, JSON validation (rejecting invalid refs type), and compatibility verification for unknown fields in browserRefs messages.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

• Add context compaction protocol messages #21: Introduces new protocol message types with similar patterns of payload struct definition and envelope switch updates.
• feat: add terminal protocol messages #22: Extends the protocol with new message types requiring envelope and message handler modifications.
• Add shared browser session protocol #30: Adds broader browser-session protocol enhancements including related browser message type infrastructure.

Poem

🐰 A protocol grows with every hop,
New browserRefs dance—they'll never stop!
Refs captured, positioned, and versioned with care,
Browser interactivity blooming everywhere! ✨

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'Add browser refs and command input protocol' accurately reflects the main changes: introduction of browserRefs message type and new browser input kind constants for commands.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch codex/browser-refs-protocol

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