feat: update extension icon with shop storefront design

- Add generate_logo.py script to create icon programmatically
- New shop icon with striped awning and display windows
- Consistent purple color scheme with Nostr Proxy extension
- Update config.json to reference new icon

Closes #150

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

config.json

@@ -2,7 +2,7 @@
   "name": "Nostr Market",
   "version": "1.1.0",
   "short_description": "Nostr Webshop/market on LNbits",
-  "tile": "/nostrmarket/static/images/bitcoin-shop.png",
+  "tile": "/nostrmarket/static/images/nostr-market.png",
   "min_lnbits_version": "1.4.0",
   "contributors": [
     {

static/images/generate_logo.py

@@ -0,0 +1,123 @@
+#!/usr/bin/env python3
+"""
+Generate the Nostr Market logo.
+Requires: pip install Pillow
+"""
+
+from PIL import Image, ImageDraw  # type: ignore[import-not-found]
+
+# Render at 4x size for antialiasing
+scale = 4
+size = 128 * scale
+final_size = 128
+
+# Consistent color scheme with Nostr Proxy
+dark_purple = (80, 40, 120)
+light_purple = (140, 100, 180)
+white = (255, 255, 255)
+
+margin = 4 * scale
+
+swoosh_center = ((128 + 100) * scale, -90 * scale)
+swoosh_radius = 220 * scale
+
+# Create rounded rectangle mask
+mask = Image.new("L", (size, size), 0)
+mask_draw = ImageDraw.Draw(mask)
+corner_radius = 20 * scale
+mask_draw.rounded_rectangle(
+    [margin, margin, size - margin, size - margin],
+    radius=corner_radius,
+    fill=255,
+)
+
+# Create background with swoosh
+bg = Image.new("RGBA", (size, size), (0, 0, 0, 0))
+bg_draw = ImageDraw.Draw(bg)
+bg_draw.rounded_rectangle(
+    [margin, margin, size - margin, size - margin],
+    radius=corner_radius,
+    fill=dark_purple,
+)
+bg_draw.ellipse(
+    [
+        swoosh_center[0] - swoosh_radius,
+        swoosh_center[1] - swoosh_radius,
+        swoosh_center[0] + swoosh_radius,
+        swoosh_center[1] + swoosh_radius,
+    ],
+    fill=light_purple,
+)
+
+# Apply rounded rectangle mask
+final = Image.new("RGBA", (size, size), (0, 0, 0, 0))
+final.paste(bg, mask=mask)
+draw = ImageDraw.Draw(final)
+
+center_x, center_y = size // 2, size // 2
+
+# Shop/storefront - wider and shorter for shop look
+shop_width = 80 * scale
+awning_height = 18 * scale
+body_height = 45 * scale
+total_height = awning_height + body_height
+
+shop_left = center_x - shop_width // 2
+shop_right = center_x + shop_width // 2
+
+# Center vertically
+awning_top = center_y - total_height // 2
+awning_bottom = awning_top + awning_height
+shop_bottom = awning_bottom + body_height
+awning_extend = 5 * scale
+
+# Draw awning background (white base)
+draw.rectangle(
+    [shop_left - awning_extend, awning_top, shop_right + awning_extend, awning_bottom],
+    fill=white,
+)
+
+# Vertical stripes on awning (alternating dark purple)
+stripe_count = 8
+stripe_width = (shop_width + 2 * awning_extend) // stripe_count
+for i in range(1, stripe_count, 2):
+    x_left = shop_left - awning_extend + i * stripe_width
+    draw.rectangle(
+        [x_left, awning_top, x_left + stripe_width, awning_bottom],
+        fill=dark_purple,
+    )
+
+# Shop body (below awning)
+draw.rectangle(
+    [shop_left, awning_bottom, shop_right, shop_bottom],
+    fill=white,
+)
+
+# Large display window (shop style)
+window_margin = 8 * scale
+window_top = awning_bottom + 6 * scale
+window_bottom = shop_bottom - 6 * scale
+# Left display window
+draw.rectangle(
+    [shop_left + window_margin, window_top, center_x - 10 * scale, window_bottom],
+    fill=dark_purple,
+)
+# Right display window
+draw.rectangle(
+    [center_x + 10 * scale, window_top, shop_right - window_margin, window_bottom],
+    fill=dark_purple,
+)
+
+# Door (center, dark purple cutout)
+door_width = 14 * scale
+door_left = center_x - door_width // 2
+draw.rectangle(
+    [door_left, window_top, door_left + door_width, shop_bottom],
+    fill=dark_purple,
+)
+
+# Downscale with LANCZOS for antialiasing
+final = final.resize((final_size, final_size), Image.LANCZOS)
+
+final.save("nostr-market.png")
+print("Logo saved to nostr-market.png")