feat(anthropic): add Claude Opus 5

[kousw]

Summary

• add claude-opus-5 to the static Anthropic model registry with its published 1M context and 128k output limits
• route all supported effort levels through adaptive thinking and enable the existing Claude API fast-mode path
• cover registry, model-list, reasoning, and fast-mode behavior with regression tests

Why

Claude Opus 5 is now available through the Claude API as claude-opus-5. Codelia's existing native Anthropic adapter already supports the required Messages API fields, so the smallest compatible change is to register the model and its capabilities explicitly.

Validation

• bun run build
• bun run test (656 JS passed, 2 integration skipped; 13 Terminal-Bench passed; 230 TUI passed)
• bun run typecheck
• bun run lint
• bun run check:deps
• bun run check:versions
• live bun run tui smoke: selected anthropic/claude-opus-5, used low effort with fast mode off, and received OK from the Claude API