Remove plan mode protocol

[glittercowboy]

Summary

• Plan Mode wire payloads are absent from task dispatch and relay envelopes.
• Browser workbench protocol messages from v0.35.0 remain intact.
• PROTOCOL.md documents the active message contract.

Verification

• go test ./...

Dependency order

1. Merge this protocol PR and tag the next module version.
2. Bump github.com/gsd-build/protocol-go in daemon.
3. Bump github.com/gsd-build/protocol-go in cloud-app/apps/relay.

Summary by CodeRabbit

• Breaking Changes
  • Removed planningEvent and planningEventAck message types from the protocol specification
  • Task message structure updated: replaced planCapability field with browserGrant field
  • Removed PlanCapability type definition from the protocol
  • Updated protocol documentation and message handling accordingly

[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: deb399f2-c5e3-4656-ad41-53a839535862

📥 Commits

Reviewing files that changed from the base of the PR and between ff3d347 and f3c648a.

📒 Files selected for processing (4)

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

💤 Files with no reviewable changes (4)

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

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📝 Walkthrough

Walkthrough

This pull request removes the planning capability feature from the protocol. The planCapability field is deleted from the task message, the PlanCapability type definition is removed, and the planningEvent and planningEventAck message types are eliminated from the protocol definition and corresponding Go implementations.

Changes

Planning Capability Removal

Layer / File(s)	Summary
Protocol Schema PROTOCOL.md	task.planCapability field and the PlanCapability type definition are removed. planningEvent and planningEventAck message types are deleted from the Daemon → Browser message section.
Message Type Definitions messages.go	Constants MsgTypePlanningEvent and MsgTypePlanningEventAck are removed. Structs PlanCapability, PlanningEvent, and PlanningEventAck are deleted. Field Task.planCapability is replaced with Task.browserGrant (*BrowserGrantContext).
Envelope Message Handling envelope.go	Case branches for MsgTypePlanningEvent and MsgTypePlanningEventAck are removed from payloadForType, causing those message types to fall through to the default error path.
Tests messages_test.go	Test functions TestPlanningEventRoundTrip, TestPlanningEventAckRoundTrip, and TestTaskPlanCapabilityRoundTrip are deleted. TestTaskAttemptFieldsRoundTrip is updated to remove Task.PlanCapability initialization and assertions.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

• feat: add task plan capability #32: Introduced the PlanCapability type and Task.planCapability field that this PR removes, making this the direct inverse of that PR.
• feat(protocol): add planning journal envelopes #39: Added planningEvent and planningEventAck message types and their struct/constant definitions that this PR deletes.
• feat: add task attempt lifecycle protocol #41: Modified the same protocol message definitions and envelope payload handling for related planning-related features.

Poem

🐰 Planning was grand, but its day has passed,
Out come the capabilities, removed at last,
browserGrant now grants the tasks their way,
Simpler protocols shine brighter today! ✨

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'Remove plan mode protocol' accurately summarizes the main change: the removal of plan mode protocol components (PlanCapability, PlanningEvent, PlanningEventAck message types) across multiple protocol files.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
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/remove-plan-mode

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