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/reference/configuration.md

@@ -228,7 +228,7 @@ Domain-specific model delegation used by the `task()` tool. When Sisyphus delega
 | `ultrabrain`         | `openai/gpt-5.4` (xhigh)        | Deep logical reasoning, complex architecture   |
 | `deep`               | `openai/gpt-5.3-codex` (medium) | Autonomous problem-solving, thorough research  |
 | `artistry`           | `google/gemini-3.1-pro` (high)  | Creative/unconventional approaches             |
-| `quick`              | `anthropic/claude-haiku-4-5`    | Trivial tasks, typo fixes, single-file changes |
+| `quick`              | `openai/gpt-5.4-mini`           | Trivial tasks, typo fixes, single-file changes |
 | `unspecified-low`    | `anthropic/claude-sonnet-4-6`   | General tasks, low effort                      |
 | `unspecified-high`   | `anthropic/claude-opus-4-6` (max) | General tasks, high effort                   |
 | `writing`            | `google/gemini-3-flash`         | Documentation, prose, technical writing        |
@@ -286,7 +286,7 @@ Disable categories: `{ "disabled_categories": ["ultrabrain"] }`
 | **ultrabrain**         | `gpt-5.4`           | `gpt-5.4` → `gemini-3.1-pro` → `claude-opus-4-6`               |
 | **deep**               | `gpt-5.3-codex`     | `gpt-5.3-codex` → `claude-opus-4-6` → `gemini-3.1-pro`         |
 | **artistry**           | `gemini-3.1-pro`    | `gemini-3.1-pro` → `claude-opus-4-6` → `gpt-5.4`               |
-| **quick**              | `claude-haiku-4-5`  | `claude-haiku-4-5` → `gemini-3-flash` → `gpt-5-nano`           |
+| **quick**              | `gpt-5.4-mini`    | `gpt-5.4-mini` → `claude-haiku-4-5` → `gemini-3-flash` → `minimax-m2.5` → `gpt-5-nano` |
 | **unspecified-low**    | `claude-sonnet-4-6` | `claude-sonnet-4-6` → `gpt-5.3-codex` → `gemini-3-flash`       |
 | **unspecified-high**   | `claude-opus-4-6`   | `claude-opus-4-6` → `gpt-5.4 (high)` → `glm-5` → `k2p5` → `kimi-k2.5` |
 | **writing**            | `gemini-3-flash`    | `gemini-3-flash` → `claude-sonnet-4-6`                         |

docs/reference/features.md

@@ -111,7 +111,7 @@ By combining these two concepts, you can generate optimal agents through `task`.
 | `ultrabrain`         | `openai/gpt-5.4` (xhigh)        | Deep logical reasoning, complex architecture decisions requiring extensive analysis                                         |
 | `deep`               | `openai/gpt-5.3-codex` (medium) | Goal-oriented autonomous problem-solving. Thorough research before action. For hairy problems requiring deep understanding. |
 | `artistry`           | `google/gemini-3.1-pro` (high)  | Highly creative/artistic tasks, novel ideas                                                                                 |
-| `quick`              | `anthropic/claude-haiku-4-5`    | Trivial tasks - single file changes, typo fixes, simple modifications                                                       |
+| `quick`              | `openai/gpt-5.4-mini`           | Trivial tasks - single file changes, typo fixes, simple modifications                                                       |
 | `unspecified-low`    | `anthropic/claude-sonnet-4-6`   | Tasks that don't fit other categories, low effort required                                                                  |
 | `unspecified-high`   | `anthropic/claude-opus-4-6` (max) | Tasks that don't fit other categories, high effort required                                                               |
 | `writing`            | `google/gemini-3-flash`         | Documentation, prose, technical writing                                                                                     |