Icon Request: prompt_suggestion

### Icon Request: prompt_suggestion

**Problem Statement**
With the rapid growth of AI-powered applications (ChatGPT, Claude, Gemini, Copilot, etc.), users need a clear visual cue for "entering a prompt" or "asking an AI." Currently, Material Design has icons for chat (`chat`, `sms`, `comment`), but none specifically represent the act of prompting an AI. The existing icons suggest conversation, not instruction/query to an AI model.

**Icon Description**
- **Basic Shape**: A speech bubble or rounded rectangle (like a text input field) with a sparkle, lightning bolt, or glow inside
- **Key Features**:
- Speech bubble shape (familiar for conversation/input)
- A sparkle, star, or lightning bolt inside to indicate "AI/magic"
- Slight angle or rotation to suggest "entering" or "submitting"
- Clean, modern look suitable for Material Design
- **Style**: Filled or Outlined, depending on the style
- **Scale**: Should be recognizable at 24dp to 48dp

**Concept Variations**
1. Speech bubble with sparkle: Classic chat bubble with a sparkle inside
2. Text field with AI glow: A rounded text input box with a glowing cursor or sparkle
3. Sparkle + Send combination: A send/forward arrow with a sparkle element

**References**
- Similar to `chat`, `sms`, `comment` but distinct
- Related icons in Material: `auto_awesome` (magic/sparkle), `rocket_launch`
- OpenAI, Anthropic, and Google's own AI products use similar concepts

**Justification**
- AI-powered features are in virtually every new app
- Need to differentiate "AI prompt" from "chat message"
- Currently no icon specifically for "prompt/AI input" in Material Design
- Growing trend: every AI app needs this icon

**Use Cases**
- AI chat apps (ChatGPT, Claude, Gemini)
- Writing assistants (Grammarly, Copilot)
- Search bars with AI integration
- "Ask AI" buttons in various apps
- Prompt libraries/collections

**Search Keywords**
prompt, AI prompt, prompt input, ask AI, magic input, sparkle chat, AI assistant

**Similar Existing Icons**
- `chat` - plain conversation
- `sms` - text message
- `auto_awesome` - magic/sparkle
- `rocket_launch` - launch/start

**Verification**
- [x] I checked https://fonts.google.com/icons and this specific icon does not exist
- [x] I searched for "prompt" and found no relevant icons
- [x] I understand I'm submitting a concept, not a finished design

**Note:** I understand that Google Fonts does not accept user submissions of finished icon designs (like SVG files) due to strict design guidelines, and that this repository is generated from upstream source files. I am submitting this as a concept for discussion, not a finished design.

This is a concept request and names no source files, tests, or implementation entry points. Start by reviewing the existing chat, sms, comment, auto_awesome, and rocket_launch icons and the repository's contribution guidance. Done means reaching agreement on a distinct prompt_suggestion concept that fits Material Design at 24dp to 48dp.

Written by the indexing model from the issue text.