fix(Earthfile): ensure proper artifact saving path

Update Earthfile to correctly save artifacts with './*' instead of '*'.

chore: add .earthlyignore file

Add .earthlyignore to ignore temporary earthly output files.

Author: flemzord

.earthlyignore

@@ -0,0 +1 @@
+.tmp-earthly-out

Earthfile

@@ -22,7 +22,7 @@ lint:
     WORKDIR /src
     COPY --dir (+tidy/src/*) /src
     DO --pass-args core+GO_LINT
-    SAVE ARTIFACT * AS LOCAL ./
+    SAVE ARTIFACT ./* AS LOCAL ./
 
 tests:
     FROM core+builder-image
@@ -45,4 +45,4 @@ generate:
     WORKDIR /src
     COPY --dir (+tidy/src/*) /src
     DO --pass-args core+GO_GENERATE
-    SAVE ARTIFACT * AS LOCAL ./
+    SAVE ARTIFACT ./* AS LOCAL ./