feat(slopbot): add LLM @mention with agentic Kagi tool calling (t-937)

- Detect @**slop** mentions via MENTION_RE regex
- Agentic loop (MAX_ITER=5): LLM decides when to call kagi_search
- Routing: Parasail primary (model discovery), Ollama qwen2.5:3b fallback
- kagi_search tool: hits Kagi API, returns top-3 snippet results
- Tickers appended to LLM reply when @mention includes $TICKER
- Logging: mention detected, tool calls, Kagi result count, backend used, response
- shell.nix: added openai + requests packages
- requirements.txt: openai>=1.0.0, requests>=2.28.0

1 files changed, 2 insertions, 0 deletions

diff --git a/shell.nix b/shell.nix
index 6bacce2..fcc0bd7 100644
--- a/shell.nix
+++ b/shell.nix
@@ -5,6 +5,8 @@ pkgs.mkShell {
     (pkgs.python3.withPackages (ps: [
       ps.zulip
       ps.yfinance
+      ps.openai
+      ps.requests
     ]))
   ];