docs: align GPT-5.5 model references

[islee23520]

Summary

• Align documentation and example configs with the GPT-5.5 model defaults already present in src/shared/model-requirements.ts.
• Add the missing GPT-5.5 prompt-file entries to Sisyphus and Hephaestus agent-local docs.
• Keep Grok/Explore/Librarian recommendation text unchanged; this PR only updates non-mini GPT-5.4 references that now point at GPT-5.5.

Testing

• GIT_MASTER=1 git diff --check HEAD~1..HEAD
• rg --pcre2 -n 'gpt-5\\.4(?!-(mini|nano))|GPT-5\\.4(?! Mini)|GPT-5\\.4(?! Mini)' docs/examples docs/guide/agent-model-matching.md docs/guide/installation.md docs/guide/orchestration.md docs/guide/overview.md docs/reference/configuration.md docs/reference/features.md
• GIT_MASTER=1 git diff HEAD~1..HEAD -- docs/examples docs/guide docs/reference | rg -n '^[+-].*(grok-code-fast-1|Grok Code Fast 1|gpt-5\\.4-mini-fast|GPT-5\\.4 Mini Fast)'

Notes

Docs-only change. No runtime behavior changes.

---

^{Need help on this PR? Tag @codesmith with what you need.}

• Let Codesmith autofix CI failures and bot reviews

---

Summary by cubic

Aligns docs, diagrams, and example configs to make openai/gpt-5.5 the default non‑mini GPT model across agents, categories, fallbacks, and flows, matching src/shared/model-requirements.ts. Adds GPT‑5.5 prompt variants for Sisyphus and Hephaestus; no runtime changes.

• Refactors
  • Updated agent defaults and fallbacks: Hephaestus/Oracle/Momus now on gpt-5.5; Prometheus/Atlas/Metis/Sisyphus‑Junior chains now include gpt-5.5; Multimodal Looker leads with gpt-5.5.
  • Revised category routing and tables: ultrabrain (xhigh), deep (medium), and unspecified-high chains use gpt-5.5; gpt-5.4-mini and gpt-5-nano unchanged.
  • Swapped gpt-5.4 → gpt-5.5 in example configs (default.jsonc, coding-focused.jsonc, planning-focused.jsonc) and modelConcurrency keys.
  • Documented GPT‑5.5-native prompts: added gpt-5-5.ts entries in src/agents/sisyphus/AGENTS.md and src/agents/hephaestus/AGENTS.md; expanded guides with Model Families/OpenCode Go sections; refreshed orchestration diagrams and installation/provider tables to reflect gpt-5.5.

^{Written for commit 766cdaf. Summary will update on new commits.}

[cubic-dev-ai]

No issues found across 11 files

Confidence score: 5/5

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

_{Auto-approved: Docs-only change aligning model references and example configs with existing codebase defaults. No runtime behavior changes, so 100% regression-free.}