feat: web search, chiptune audio, cleaner intent routing

- Add web_search tool (Tavily, Brave, SearXNG, DuckDuckGo fallback)
  with auto-provider detection from env vars
- Fix DDG parser to handle single-quoted HTML attributes
- Add chiptune synthesizer for boot screen (square/triangle/noise,
  4-channel tracker pattern, pipes to aplay/paplay, silent fallback)
- Simplify intent classify prompt — 6 lines, agent-first, no bloat
- Add web_search to agent, subagent, and parallel-safe tool lists
- Tell agent it can call read-only tools in parallel

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: halfaipg

agent.go

@@ -60,10 +60,12 @@ Available tools:
 - multi_edit: Batch multiple edits across files. Per-file atomicity with rollback.
 - list_files: List directory contents or glob for files (e.g. "**/*.go").
 - search_files: Regex search across files (powered by ripgrep). Find definitions, usages, etc.
+- web_search: Search the web. Use for current info, docs, versions, error solutions, or anything not in local files.
 - dispatch_agent: Spawn a read-only research subagent to investigate questions in isolated context.
 - shell: Run any shell command. Use for builds, tests, git, package management.
 
 Guidelines:
+- You can call multiple tools in parallel — read_file, list_files, search_files, web_search, and dispatch_agent all run concurrently
 - Use list_files and search_files to explore the project before making changes
 - Read files before editing them — understand existing code first
 - Make targeted, minimal changes — don't rewrite entire files unnecessarily

app.go

@@ -53,6 +53,7 @@ func (m appModel) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 	case screenBoot:
 		switch msg.(type) {
 		case bootDoneMsg:
+			m.boot.audio.Stop() // stop boot music (nil-safe)
 			m.screen = screenChat
 			return m, tea.Batch(
 				m.chat.Init(),