refactor: remove terminal MCP, Playwright, and commands infrastructure

- Remove terminal/tmux MCP from voice LLM - it now only uses agent-control MCP
- Remove Playwright MCP auto-injection from Claude and Codex agents
- Remove commands state from session, store, and UI
- Remove present_artifact tool and guidelines from voice prompt
- Update agent-prompt.md examples to focus on agents instead of commands
- Remove @huggingface/transformers dependency and test scripts
- Add expandTilde utility to utils/path.ts

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

package-lock.json

@@ -1701,9 +1701,9 @@
       }
     },
     "node_modules/@emnapi/runtime": {
-      "version": "1.6.0",
-      "resolved": "https://registry.npmjs.org/@emnapi/runtime/-/runtime-1.6.0.tgz",
-      "integrity": "sha512-obtUmAHTMjll499P+D9A3axeJFlhdjOWdKUNs/U6QIGT7V5RjcUW1xToAzjvmgTSQhDbYn/NwfTRoJcQ2rNBxA==",
+      "version": "1.8.1",
+      "resolved": "https://registry.npmjs.org/@emnapi/runtime/-/runtime-1.8.1.tgz",
+      "integrity": "sha512-mehfKSMWjjNol8659Z8KxEMrdSJDDot5SXMq00dM8BN4o+CLNXQ0xH2V7EchNHV4RmbZLmmPdEaXZc5H2FXmDg==",
       "dev": true,
       "license": "MIT",
       "optional": true,