feat(agent-priority): inject order field for deterministic agent Tab cycling

[kuitos]

Summary

• Inject explicit order field (1-4) into four core agents so Tab cycling order is preserved after OpenCode 1.3.0+ alphabetical sorting
• Pre-empts upstream support: once anomalyco/opencode#19127 merges, the order takes effect automatically

Problem

OpenCode 1.3.0 introduced alphabetical agent sorting (#18261), which overrides oh-my-opencode's intended agent order. Tab cycle changed from Sisyphus → Hephaestus → Prometheus → Atlas to Sisyphus -> Atlas → Hephaestus → Prometheus.

The existing reorderAgentsByPriority() only controlled object insertion order, which OpenCode's sortBy ignores.

Solution

Refactored reorderAgentsByPriority() to inject an order field into each core agent config:

Agent	Order
Sisyphus	1
Hephaestus	2
Prometheus	3
Atlas	4

The order field is part of the upstream PR (anomalyco/opencode#19127, refs #7372). Until merged, the field is harmlessly ignored by OpenCode.

Changes

• src/plugin-handlers/agent-priority-order.ts: Refactored CORE_AGENT_ORDER to carry order values, added injectOrderField() helper
• src/plugin-handlers/agent-config-handler.test.ts: Updated test expectation to include injected order field

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Summary by cubic

Adds an explicit order field to core agents to enforce deterministic Tab cycling despite OpenCode 1.3.0 alphabetical sorting. Prepares for upstream order support so the order applies automatically when available and is a no-op until then.

• New Features
  • Assigned order: Sisyphus 1, Hephaestus 2, Prometheus 3, Atlas 4.
  • Refactored reorderAgentsByPriority() to inject order via injectOrderField().
  • Updated tests to expect order on builtin Sisyphus.

^{Written for commit 5befb60. Summary will update on new commits.}

[cubic-dev-ai]

No issues found across 2 files

Confidence score: 5/5

• Automated review surfaced no issues in the provided summaries.
• No files require special attention.

_{Auto-approved: Injecting an 'order' field is a safe, additive change. It restores intended behavior following upstream changes and is designed to be backwards compatible.}

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[kuitos]

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