fix(cli): actually use ripgrep in evo grep (fixes #94) - #100

Problem

cmd_ws_grep selects ripgrep via:

if (which.exit_code or 1) == 0 and which.stdout.strip():

which rg exits 0 when rg is present, but 0 or 1 → 1, so 1 == 0 is False; when rg is absent the exit code is 1 → 1 or 1 → 1, again False. The condition is False in every case, so the rg branch is dead — evo grep always runs grep -rn.

Because rg and grep differ in regex dialect (\d, \b, lookarounds) and in .gitignore handling, patterns intended for rg match differently or error, and ignored dirs get searched. The documented "prefer rg, fall back to grep" contract never fires.

Fix

if which.exit_code == 0 and which.stdout.strip():

Tests

tests/unit/test_ws_grep_ripgrep.py (TDD, failing first) drives cmd_ws_grep with a fake executor:

• rg present → the search command is rg
• rg absent → falls back to grep

Fixes #94.