feat(categories): change quick category default model from claude-haiku-4-5 to gpt-5.4-mini

GPT-5.4-mini provides stronger reasoning at comparable speed and cost.
Haiku remains as the next fallback priority in the chain.

Changes:
- DEFAULT_CATEGORIES quick model: anthropic/claude-haiku-4-5 → openai/gpt-5.4-mini
- Fallback chain: gpt-5.4-mini → haiku → gemini-3-flash → minimax-m2.5 → gpt-5-nano
- OpenAI-only catalog: quick uses gpt-5.4-mini directly
- Think-mode: add gpt-5-4-mini and gpt-5-4-nano high variants
- Update all documentation references

docs/guide/orchestration.md

@@ -298,7 +298,7 @@ task({ category: "quick", prompt: "..." }); // "Just get it done fast"
 | `visual-engineering` | Gemini 3.1 Pro         | Frontend, UI/UX, design, styling, animation                 |
 | `ultrabrain`         | GPT-5.4 (xhigh)        | Deep logical reasoning, complex architecture decisions      |
 | `artistry`           | Gemini 3.1 Pro (high)  | Highly creative or artistic tasks, novel ideas              |
-| `quick`              | Claude Haiku 4.5       | Trivial tasks - single file changes, typo fixes             |
+| `quick`              | GPT-5.4 Mini           | Trivial tasks - single file changes, typo fixes             |
 | `deep`               | GPT-5.3 Codex (medium) | Goal-oriented autonomous problem-solving, thorough research |
 | `unspecified-low`    | Claude Sonnet 4.6      | Tasks that don't fit other categories, low effort           |
 | `unspecified-high`   | Claude Opus 4.6 (max)  | Tasks that don't fit other categories, high effort          |