* Update claude-api skill: Claude Opus 5
- Add Claude Opus 5 (`claude-opus-5`) as the default model across all
SDK examples, model tables, pricing, and migration guidance.
- Add an Opus 5 migration section covering the API changes that come
with it, and move Opus 4.8 into the previous-generation slot.
- Drop the Opus 4.7 fast-mode guidance, which no longer applies.
- Scope the server-side fallbacks beta header to the current version.
* Update claude-api skill: Opus 5 fast-follow corrections
- Server-side refusal fallbacks are available on Claude Platform on AWS,
not just the Claude API. Correct the availability statements in
SKILL.md, the migration guide, and the platform-availability table.
- Simplify the effort guidance: start at `high` (the API default) and
sweep down, rather than starting at `xhigh` for coding work.
- Add a time-to-first-token section with the prompt instruction that
reduces pre-answer thinking on latency-sensitive routes.
- Replace the two separate thinking-disabled mitigations with the single
combined instruction that covers both failure modes.