Keep the database files, logs and binaries out of the build context (closes #120)

The daemon's database is db.sqlite with its -wal and -shm files, which
the .db patterns in .dockerignore and .gitignore did not match, so a
database left in the clone shipped in the image's source archive.
.dockerignore now also excludes the logs and the .exe, .dll, .so and
.dylib files .gitignore already ignores. A test opens a database and
checks that .dockerignore has an any-depth pattern for each of its
files.

Model: opus-5-5

.dockerignore

@@ -73,7 +73,8 @@
 
 # This repository's host-built artifacts: `make build` writes bin/, `go
 # build` in the root the binaries, `make run` log.txt, `make asupdate` its
-# .tmp file; test binaries, coverage profiles and source archives.
+# .tmp file; logs, test binaries, coverage profiles, source archives, and
+# the binaries and libraries a build for another platform writes.
 /bin
 /routewatch
 /asinfo-gen
@@ -82,15 +83,24 @@
 /out
 /pkg/asinfo/asdata.json
 **/*.tar.zst
+**/*.log
 **/*.test
 **/*.out
 **/*.tmp
+**/*.exe
+**/*.dll
+**/*.so
+**/*.dylib
 
 # Local databases. The image carries a source archive of the whole build
-# context, so these would otherwise ship inside it.
+# context, so these would otherwise ship inside it. The daemon's database
+# is db.sqlite, with its -wal and -shm files while it runs.
 **/*.db
 **/*.db-journal
 **/*.db-wal
+**/*.sqlite
+**/*.sqlite-wal
+**/*.sqlite-shm
 
 # A local Go workspace points at directories outside the build context.
 /go.work