Move plugins to manifest, pin Docker version, add Makefile

- Add plugins.txt listing all plugins for reproducible installs
- Add Makefile with setup/start/stop/install-plugins targets
- Remove user/plugins/ from git tracking
- Pin Docker image to 1.7.49.5-ls244

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

plugins/problems/scss/utilities/_text.scss

@@ -1,64 +0,0 @@
-// Text
-// Text alignment utilities
-.text-left {
-  text-align: left;
-}
-
-.text-right {
-  text-align: right;
-}
-
-.text-center {
-  text-align: center;
-}
-
-.text-justify {
-  text-align: justify;
-}
-
-// Text transform utilities
-.text-lowercase {
-  text-transform: lowercase;
-}
-
-.text-uppercase {
-  text-transform: uppercase;
-}
-
-.text-capitalize {
-  text-transform: capitalize;
-}
-
-// Text style utilities
-.text-normal {
-  font-weight: normal;
-}
-
-.text-bold {
-  font-weight: bold;
-}
-
-.text-italic {
-  font-style: italic;
-}
-
-.text-large {
-  font-size: 1.2em;
-}
-
-// Text overflow utilities
-.text-ellipsis {
-  @include text-ellipsis();
-}
-
-.text-clip {
-  overflow: hidden;
-  text-overflow: clip;
-  white-space: nowrap;
-}
-
-.text-break {
-  hyphens: auto;
-  word-break: break-word;
-  word-wrap: break-word;
-}