feat(tools): add web_search_tool for internet search

Add native web search capability that works regardless of LLM tool-calling
support. This is particularly useful for GLM models via Z.AI that don't
reliably support standard tool calling formats.

Features:
- DuckDuckGo provider (free, no API key required)
- Brave Search provider (optional, requires API key)
- Configurable max results and timeout
- Enabled by default

Configuration (config.toml):
  [web_search]
  enabled = true
  provider = "duckduckgo"
  max_results = 5

The tool allows agents to search the web for current information without
requiring proper tool calling support from the LLM.

Also includes CI workflow fix for first-interaction action inputs.

Cargo.toml

@@ -43,6 +43,9 @@ prometheus = { version = "0.14", default-features = false }
 # Base64 encoding (screenshots, image data)
 base64 = "0.22"
 
+# URL encoding for web search
+urlencoding = "2.1"
+
 # Optional Rust-native browser automation backend
 fantoccini = { version = "0.22.0", optional = true, default-features = false, features = ["rustls-tls"] }