chore: ignore host-test binaries by shape, not by a list that goes stale

`make host_tests` writes its binaries beside their sources, inside a tracked
directory. .gitignore named five of them individually, and the list had fallen
behind the Makefile: test_csi_sanitize, test_mmwave_detect and test_thermal
were built by the default target, ignored by nothing, and got committed by
accident on two contribution branches.

Enumerating targets cannot hold -- every new host test needs someone to
remember this file. So ignore by shape instead: in that directory every source
carries an extension and no binary does.

    firmware/esp32-csi-node/test/test_*
    firmware/esp32-csi-node/test/fuzz_*
    !firmware/esp32-csi-node/test/*.*

Verified rather than reasoned about. After building every host test,
`git status --porcelain` reports only this file. `git check-ignore` confirms
all ten binaries are ignored -- including test_edge_grid_he and
test_edge_grid_pre_he, which are not on main yet -- while the .c sources, the
Makefile, the README and the corpus seeds stay tracked.

Co-Authored-By: claude-flow <ruv@ruv.net>
Claude-Session: https://claude.ai/code/session_01BHNNWbmKvxXrVaEDwXEBNo

.gitignore

@@ -17,11 +17,16 @@ firmware/esp32-csi-node/sdkconfig.defaults.bak
 firmware/esp32-hello-world/sdkconfig.old
 
 # Host-built firmware test binaries (compiled from test/*.c, not source)
-firmware/esp32-csi-node/test/test_adr110
-firmware/esp32-csi-node/test/test_vitals
-firmware/esp32-csi-node/test/fuzz_serialize
-firmware/esp32-csi-node/test/fuzz_edge
-firmware/esp32-csi-node/test/fuzz_nvs
+# Compiled host-test and fuzz binaries. The Makefile writes them beside their
+# sources, so they land in a tracked directory. Ignore them by SHAPE rather
+# than by name: every source here carries an extension and no binary does.
+#
+# This replaced a hand-maintained list of five targets, which had gone stale --
+# test_csi_sanitize, test_mmwave_detect and test_thermal were all built by
+# `make host_tests`, ignored by nothing, and got committed by accident.
+firmware/esp32-csi-node/test/test_*
+firmware/esp32-csi-node/test/fuzz_*
+!firmware/esp32-csi-node/test/*.*
 firmware/esp32-csi-node/test/*.exe
 firmware/esp32-csi-node/test/*.obj