brainstorm

<objective> Turn unformed idea into branching exploration tree, then distill into spec. Idea mode = pure divergence — grow tree of directions, deepen promising branches, prune others, save result. No premature convergence. Run `breakdown` on tree when ready: asks distillation questions, writes spec section-by-section. NOT for implementation or code-gen — see `develop` plugin (requires `develop` plugin). > **HARD GATE:** Do NOT take any implementation action — writing code, creating files, scaffolding — until user approves design (spec). Applies regardless of perceived simplicity. Simple idea can have short tree and spec, but process never skipped. </objective> <inputs> - **$ARGUMENTS**: required — fuzzy idea, goal, or feature request in any form; one sentence enough - **`--tight`** — reduced-ceremony mode: see per-step caps below — 5/5/1 bounds vs default 10/10/2. Good for well-scoped ideas where problem already understood. - **`--deep`** — extended-ceremony mode: 15/15/3 bounds vs default 10/10/2. Good for ambiguous problems where more exploration valuable. - Default (no flag): behaviour unchanged — 10/10/2 bounds. - **`--type <type>`** — optional type hint for idea mode. One of: `application` (app/service with users/endpoints), `workflow` (automation, pipeline, script), `utility` (helper library, tool, CLI), `config` (`.claude/` agents/skills/rules), `research` (investigation, survey, experiment design). Affects Step 1 scan patterns and Step 2 question framing. Omit...