fix: /version command + recover qwen tool calls from text content

[Doorman11991]

Summary

Closes #40, closes #36.

#40 — /version returns "Unknown"

Reporter ran /version and got Unknown: /version. Type /help. The command was advertised by the command palette and the help table but never had a handler.

Added case '/version': case '/v': to bin/commands.js. Reads package.json so the value can never drift, prints the description and Node X on platform/arch for support context. /version is now in /help and the README command table.

#36 — qwen2.5-coder:14b spills tool JSON into chat

Reporter pointed Ollama at qwen2.5-coder:14b and asked “what files are in this directory?”. Instead of the tool running, the raw <tool_call>{"name":"shell",...}</tool_call> blob landed in chat.

Root cause: some local-model + Ollama OpenAI-compat combinations emit the tool invocation as text in message.content rather than populating the structured tool_calls field. The agent loop in bin/smallcode.js only checks message.tool_calls, so the call is treated as plain prose.

Added src/tools/tool_call_extractor.js — a defensive recovery layer that runs immediately after the model response is decoded. It detects four shapes and lifts them into the proper tool_calls field:

• <tool_call>{...}</tool_call> — Hermes / qwen2.5 native template
• ```json ... ``` and ```tool_call ... ``` fenced blocks
• A bare leading JSON object/array (whole content is JSON)
• { "function": { "name", "arguments" } }, { "name", "arguments" }, and { "tool", "args" } body forms

Other niceties:

• Tolerates trailing-comma JSON (qwen quirk).
• Filters out calls that reference unknown tool names — the chat output is preferred over inventing calls.
• Strips the lifted JSON from message.content so the user doesn't see it twice.

Wired into the three response-handling sites that exist today: bin/smallcode.js (interactive agent loop), src/api/index.js (programmatic SDK), and src/session/parallel_executor.js (parallel-step planner). All three already-structured-tool_calls paths continue working unchanged.

Verification

E2E tests in .test-workspace/ (workspace-local, gitignored):

• tool_call_extractor_test.js — 10 cases including all four shapes, multiple calls per message, unknown-tool rejection, prose passthrough, trailing-comma repair, and the OpenAI-shaped variant. 10/10 pass.
• version_command_test.js — verifies /version, /v, and that unknown slashes still report "Unknown:". 3/3 pass.

Existing tui_unit_test.js still passes 11/11.

Files

• src/tools/tool_call_extractor.js — new (168 lines)
• bin/commands.js — /version + /v cases, /help line
• bin/smallcode.js — extractor call after response.choices[0].message
• src/api/index.js — same wiring for the SDK path
• src/session/parallel_executor.js — same wiring for parallel steps
• README.md — /version row in the command table
• CHANGELOG.md — Unreleased entry