feat: add agent icon assets and refresh-favicon skill (#1499)

Download favicon/icons for all 6 agents into assets/agents/:
- claude.png    — Anthropic GitHub org avatar (4.5K)
- openclaw.png  — openclaw.ai/apple-touch-icon.png (5.8K)
- zeroclaw.png  — zeroclaw-labs GitHub org avatar (11K)
- codex.png     — OpenAI GitHub org avatar (4.0K)
- opencode.svg  — opencode.ai/favicon.svg (612B)
- kilocode.png  — Kilo-Org GitHub org avatar (1.3K)

Update manifest.json icon fields to point to raw.githubusercontent.com
URLs for the local files (stable, CDN-served, versioned in repo).

Add assets/agents/.sources.json tracking each agent's canonical source
URL and extension for use by the refresh-favicon skill.

Add .claude/skills/refresh-favicon/SKILL.md — a skill that re-downloads
all agent icons from their source URLs, detects content types, updates
.sources.json, and syncs manifest.json icon fields.

Co-authored-by: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

.claude/skills/refresh-favicon/SKILL.md

@@ -0,0 +1,76 @@
+# Refresh Agent Favicons
+
+Re-download all agent icon/favicon files into `assets/agents/` and keep the manifest `icon` fields in sync.
+
+## When to use
+
+Run this when:
+- An agent's logo changes (new branding, new org avatar)
+- An icon URL breaks (404 or stale redirect)
+- A new agent is added to the manifest without a local icon
+- You suspect an icon file is corrupt or outdated
+
+## Arguments
+
+- `--agent <id>` — Refresh only the specified agent (e.g. `--agent openclaw`). Omit to refresh all.
+- `--dry-run`    — Print what would be downloaded without writing files.
+
+## Procedure
+
+### Step 1: Read the manifest
+
+```bash
+python3 -c "import json; d=json.load(open('manifest.json')); [print(k, v.get('icon','')) for k,v in d['agents'].items()]"
+```
+
+### Step 2: Determine source URLs
+
+For each agent, the canonical icon source URL is tracked in `assets/agents/.sources.json`.
+If it doesn't exist, fall back to the current `icon` field in `manifest.json`.
+
+### Step 3: Download each icon
+
+For each agent (or the specified `--agent`):
+
+1. Fetch the source URL with `curl -fsSL -o assets/agents/{agent}.{ext}`
+2. Detect the file extension from the `Content-Type` header:
+   - `image/svg+xml` → `.svg`
+   - `image/png`     → `.png`
+   - `image/jpeg`    → `.jpg`
+   - `image/x-icon` or `image/vnd.microsoft.icon` → `.ico`
+3. If the HTTP response is not 200, print a warning and skip that agent
+4. If `--dry-run`, print what would be downloaded without writing
+
+### Step 4: Update assets/.sources.json
+
+Write (or update) `assets/agents/.sources.json` with the mapping of each agent to its source URL and detected extension:
+
+```json
+{
+  "claude":    { "url": "https://...", "ext": "png" },
+  "openclaw":  { "url": "https://...", "ext": "png" },
+  ...
+}
+```
+
+### Step 5: Update manifest.json icon fields
+
+For each refreshed agent, set `icon` in `manifest.json` to the raw GitHub URL:
+
+```
+https://raw.githubusercontent.com/OpenRouterTeam/spawn/main/assets/agents/{agent}.{ext}
+```
+
+### Step 6: Verify
+
+```bash
+ls -lh assets/agents/
+python3 -c "import json; d=json.load(open('manifest.json')); [print(k, d['agents'][k].get('icon','MISSING')) for k in d['agents']]"
+```
+
+### Step 7: Summary
+
+Print a summary:
+- Agents refreshed (with old → new byte sizes)
+- Agents skipped (errors or dry-run)
+- Any icon URL changes detected

assets/agents/.sources.json

@@ -0,0 +1,8 @@
+{
+  "claude":   { "url": "https://avatars.githubusercontent.com/u/76263028?s=200&v=4", "ext": "png" },
+  "openclaw": { "url": "https://openclaw.ai/apple-touch-icon.png",                    "ext": "png" },
+  "zeroclaw": { "url": "https://avatars.githubusercontent.com/u/261820148?s=200&v=4", "ext": "png" },
+  "codex":    { "url": "https://avatars.githubusercontent.com/u/14957082?s=200&v=4",  "ext": "png" },
+  "opencode": { "url": "https://opencode.ai/apple-touch-icon.png",                     "ext": "png" },
+  "kilocode": { "url": "https://avatars.githubusercontent.com/u/201822503?s=200&v=4", "ext": "png" }
+}

manifest.json

@@ -27,8 +27,10 @@
           "bypassPermissionsModeAccepted": true
         }
       },
-      "icon": "https://avatars.githubusercontent.com/u/76263028?s=200&v=4",
-      "featured_cloud": ["sprite"]
+      "icon": "https://raw.githubusercontent.com/OpenRouterTeam/spawn/main/assets/agents/claude.png",
+      "featured_cloud": [
+        "sprite"
+      ]
     },
     "openclaw": {
       "name": "OpenClaw",
@@ -48,12 +50,14 @@
           "default": "openrouter/auto"
         }
       },
-      "icon": "https://openclaw.ai/apple-touch-icon.png",
-      "featured_cloud": ["fly"]
+      "icon": "https://raw.githubusercontent.com/OpenRouterTeam/spawn/main/assets/agents/openclaw.png",
+      "featured_cloud": [
+        "fly"
+      ]
     },
     "zeroclaw": {
       "name": "ZeroClaw",
-      "description": "Fast, small, fully autonomous AI assistant infrastructure — deploy anywhere, swap anything",
+      "description": "Fast, small, fully autonomous AI assistant infrastructure \u2014 deploy anywhere, swap anything",
       "url": "https://github.com/zeroclaw-labs/zeroclaw",
       "install": "curl -LsSf https://raw.githubusercontent.com/zeroclaw-labs/zeroclaw/main/scripts/install.sh | bash -s -- --install-rust --install-system-deps",
       "launch": "zeroclaw agent",
@@ -62,8 +66,11 @@
         "ZEROCLAW_PROVIDER": "openrouter"
       },
       "notes": "Rust-based agent framework built by Harvard/MIT/Sundai.Club communities. Natively supports OpenRouter via OPENROUTER_API_KEY + ZEROCLAW_PROVIDER=openrouter. Requires compilation from source (~5-10 min).",
-      "icon": "https://avatars.githubusercontent.com/u/261820148?s=200&v=4",
-      "featured_cloud": ["hetzner", "fly"]
+      "icon": "https://raw.githubusercontent.com/OpenRouterTeam/spawn/main/assets/agents/zeroclaw.png",
+      "featured_cloud": [
+        "hetzner",
+        "fly"
+      ]
     },
     "codex": {
       "name": "Codex CLI",
@@ -77,8 +84,10 @@
         "OPENROUTER_API_KEY": "${OPENROUTER_API_KEY}"
       },
       "notes": "Works with OpenRouter via OPENAI_BASE_URL override pointing to openrouter.ai/api/v1",
-      "icon": "https://avatars.githubusercontent.com/u/14957082?s=200&v=4",
-      "featured_cloud": ["fly"]
+      "icon": "https://raw.githubusercontent.com/OpenRouterTeam/spawn/main/assets/agents/codex.png",
+      "featured_cloud": [
+        "fly"
+      ]
     },
     "opencode": {
       "name": "OpenCode",
@@ -90,8 +99,10 @@
         "OPENROUTER_API_KEY": "${OPENROUTER_API_KEY}"
       },
       "notes": "Natively supports OpenRouter via OPENROUTER_API_KEY env var. Go-based TUI using Bubble Tea.",
-      "icon": "https://opencode.ai/favicon.svg",
-      "featured_cloud": ["daytona"]
+      "icon": "https://raw.githubusercontent.com/OpenRouterTeam/spawn/main/assets/agents/opencode.png",
+      "featured_cloud": [
+        "daytona"
+      ]
     },
     "kilocode": {
       "name": "Kilo Code",
@@ -105,8 +116,10 @@
         "OPENROUTER_API_KEY": "${OPENROUTER_API_KEY}"
       },
       "notes": "Natively supports OpenRouter as a provider via KILO_PROVIDER_TYPE=openrouter. CLI installable via npm as @kilocode/cli, invocable as 'kilocode' or 'kilo'.",
-      "icon": "https://avatars.githubusercontent.com/u/201822503?s=200&v=4",
-      "featured_cloud": ["fly"]
+      "icon": "https://raw.githubusercontent.com/OpenRouterTeam/spawn/main/assets/agents/kilocode.png",
+      "featured_cloud": [
+        "fly"
+      ]
     }
   },
   "clouds": {