Add icon PNG files and load from disk

[SamMorrowDrums]

Changes

Adds icon PNG files extracted from inline base64 strings.

Icon location: mcp_starter/assets/icons/

Files

• abacus.png
• hourglass.png
• package.png
• robot.png
• sun_behind_cloud.png
• waving_hand.png

TODO (for Copilot or maintainer)

After merging this PR, update icons.py to:

1. Delete the inline base64 strings
2. Load icons from assets/icons/ at runtime:

import base64
from pathlib import Path

ICONS_DIR = Path(__file__).parent / "assets" / "icons"

def load_icon(name: str) -> str:
    path = ICONS_DIR / f"{name}.png"
    with open(path, "rb") as f:
        return f"data:image/png;base64,{base64.b64encode(f.read()).decode()}"

WAVING_HAND_ICON = load_icon("waving_hand")
SUN_BEHIND_CLOUD_ICON = load_icon("sun_behind_cloud")
# etc...

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Icons from Microsoft Fluent UI Emoji (MIT License)