feat: add MiniMax as LLM provider

Add MiniMax (api.minimax.io) as a fifth LLM provider option alongside
Anthropic, OpenAI, Gemini, and Codex. MiniMax offers an
OpenAI-compatible Chat Completions API with the M2.5 model (204K
context window).

Changes:
- lib/llm/minimax.mjs: new provider using raw fetch (no SDK)
- lib/llm/index.mjs: register MiniMax in the factory
- .env.example, crucix.config.mjs, README.md: document the new option
- test/llm-minimax.test.mjs: 10 unit tests (node:test)
- test/llm-minimax-integration.test.mjs: live API integration test

Usage:
  LLM_PROVIDER=minimax
  LLM_API_KEY=sk-...
  LLM_MODEL=MiniMax-M2.5          # optional, this is the default

README.md

@@ -148,10 +148,10 @@ Alerts are delivered as rich embeds with color-coded sidebars: red for FLASH, ye
 **Optional dependency:** The full bot requires `discord.js`. Install it with `npm install discord.js`. If it's not installed, Crucix automatically falls back to webhook-only mode.
 
 ### Optional LLM Layer
-Connect any of 4 LLM providers for enhanced analysis:
+Connect any of 5 LLM providers for enhanced analysis:
 - **AI trade ideas** — quantitative analyst producing 5-8 actionable ideas citing specific data
 - **Smarter alert evaluation** — LLM classifies signals into FLASH/PRIORITY/ROUTINE tiers with cross-domain correlation and confidence scoring
-- Providers: Anthropic Claude, OpenAI, Google Gemini, OpenAI Codex (ChatGPT subscription)
+- Providers: Anthropic Claude, OpenAI, Google Gemini, OpenAI Codex (ChatGPT subscription), MiniMax
 - Graceful fallback — when LLM is unavailable, a rule-based engine takes over alert evaluation. LLM failures never crash the sweep cycle.
 
 ---
@@ -184,7 +184,7 @@ These three unlock the most valuable economic and satellite data. Each takes abo
 
 ### LLM Provider (optional, for AI-enhanced ideas)
 
-Set `LLM_PROVIDER` to one of: `anthropic`, `openai`, `gemini`, `codex`
+Set `LLM_PROVIDER` to one of: `anthropic`, `openai`, `gemini`, `codex`, `minimax`
 
 | Provider | Key Required | Default Model |
 |----------|-------------|---------------|
@@ -192,6 +192,7 @@ Set `LLM_PROVIDER` to one of: `anthropic`, `openai`, `gemini`, `codex`
 | `openai` | `LLM_API_KEY` | gpt-5.4 |
 | `gemini` | `LLM_API_KEY` | gemini-3.1-pro |
 | `codex` | None (uses `~/.codex/auth.json`) | gpt-5.3-codex |
+| `minimax` | `LLM_API_KEY` | MiniMax-M2.5 |
 
 For Codex, run `npx @openai/codex login` to authenticate via your ChatGPT subscription.
 
@@ -261,12 +262,13 @@ crucix/
 │       └── jarvis.html        # Self-contained Jarvis HUD
 │
 ├── lib/
-│   ├── llm/                   # LLM abstraction (4 providers, raw fetch, no SDKs)
+│   ├── llm/                   # LLM abstraction (5 providers, raw fetch, no SDKs)
 │   │   ├── provider.mjs       # Base class
 │   │   ├── anthropic.mjs      # Claude
 │   │   ├── openai.mjs         # GPT
 │   │   ├── gemini.mjs         # Gemini
 │   │   ├── codex.mjs          # Codex (ChatGPT subscription)
+│   │   ├── minimax.mjs        # MiniMax (M2.5, 204K context)
 │   │   ├── ideas.mjs          # LLM-powered trade idea generation
 │   │   └── index.mjs          # Factory: createLLMProvider()
 │   ├── delta/                 # Change tracking between sweeps
@@ -368,7 +370,7 @@ All settings are in `.env` with sensible defaults:
 |----------|---------|-------------|
 | `PORT` | `3117` | Dashboard server port |
 | `REFRESH_INTERVAL_MINUTES` | `15` | Auto-refresh interval |
-| `LLM_PROVIDER` | disabled | `anthropic`, `openai`, `gemini`, or `codex` |
+| `LLM_PROVIDER` | disabled | `anthropic`, `openai`, `gemini`, `codex`, or `minimax` |
 | `LLM_API_KEY` | — | API key (not needed for codex) |
 | `LLM_MODEL` | per-provider default | Override model selection |
 | `TELEGRAM_BOT_TOKEN` | disabled | For Telegram alerts + bot commands |