tox: try using uv for CI, should result in speedup

see https://github.com/karlicoss/HPI/issues/391

tox.ini

@@ -17,6 +17,9 @@ passenv =
     PYTHONPYCACHEPREFIX
     MYPY_CACHE_DIR
     RUFF_CACHE_DIR
+setenv =
+    HPI_MODULE_INSTALL_USE_UV=true
+uv_seed = true  # seems necessary so uv creates separate venvs per tox env?
 
 
 # note: --use-pep517 below is necessary for tox --parallel flag to work properly
@@ -24,7 +27,6 @@ passenv =
 
 
 [testenv:ruff]
-install_command = {envpython} -m pip install --use-pep517 {opts} {packages}
 deps =
     -e .[testing]
 commands =
@@ -33,7 +35,6 @@ commands =
 
 # just the very core tests with minimal dependencies
 [testenv:tests-core]
-install_command = {envpython} -m pip install --use-pep517 {opts} {packages}
 deps =
     -e .[testing]
 commands =
@@ -56,9 +57,9 @@ setenv =
     # TODO not sure if need it?
     MY_CONFIG=nonexistent
     HPI_TESTS_USES_OPTIONAL_DEPS=true
-install_command = {envpython} -m pip install --use-pep517 {opts} {packages}
 deps =
     -e .[testing]
+    uv              # for hpi module install
     cachew
     ijson  # optional dependency for various modules
 commands =
@@ -93,7 +94,6 @@ commands =
 
 
 [testenv:mypy-core]
-install_command = {envpython} -m pip install --use-pep517 {opts} {packages}
 deps =
     -e .[testing,optional]
     orgparse  # for core.orgmode
@@ -109,9 +109,9 @@ commands =
 # specific modules that are known to be mypy compliant (to avoid false negatives)
 # todo maybe split into separate jobs? need to add comment how to run
 [testenv:mypy-misc]
-install_command = {envpython} -m pip install --use-pep517 {opts} {packages}
 deps =
     -e .[testing,optional]
+    uv              # for hpi module install
     lxml-stubs      # for my.smscalls
     types-protobuf  # for my.google.maps.android
     types-Pillow    # for my.photos