chore(models): update Claude Opus metadata to 4.8

[shiny-code-bot]

Objective

Update Every Code's Claude Opus-facing model/tool metadata for Anthropic's Claude Opus 4.8 release on May 28, 2026.

Anthropic announced Claude Opus 4.8 as available everywhere today: https://www.anthropic.com/news/claude-opus-4-8

Finish Line

Every Code references Claude Opus 4.8 wherever the current/latest Opus model is surfaced or selected, and stale Opus references are removed or intentionally preserved with a clear reason.

Current Status

State: Active
Next action: Locate all Every Code model metadata, defaults, docs, and tests that mention the current Claude Opus version.
Blocked by: None
Last verified: 2026-05-28

Scope

• In: Current/latest Claude Opus model metadata, defaults, user-facing references, docs, and tests in this repository.
• Out: Building a general auto-update system for external binaries; track that in feat(updates): manage stale external agent CLI binaries #178.

Acceptance Criteria

• All current/latest Claude Opus references that should move are updated to Claude Opus 4.8.
• Any intentionally retained older Opus references are clearly test fixtures, history, compatibility entries, or otherwise justified.
• Relevant docs/tests are updated with the same model naming.
• Required repository validation passes with ./build-fast.sh.

Relationships

Related to #178, which covers managed update detection for external agent CLI binaries.

Validation

• Search for stale Opus references after implementation.
• Run ./build-fast.sh from the repository root.

Decisions

• Split from the external CLI updater feature so the model update can land quickly.

Open Questions

• Which exact internal identifiers, aliases, or provider-specific names should map to Claude Opus 4.8?

[cbusillo]

Every Code is working on this issue from Chris-Studio.

Session: every-code-every-code-cbusillo-code-177-2ffae16fdfd05f2f
Launchplane request: every-code-cbusillo-code-177-2ffae16fdfd05f2f

[cbusillo]

Implemented in #204, merged as d9ae07d. Validation: ./build-fast.sh passed and JetBrains changed-files inspection was clean.