feat: add theme engine + standardize params.yaml

Re-implements theme engine in Tailwind from the previous Bootstrap version.

Re-organizes appearance params in `params.yaml`.

Also,
- edit Readme
- add popular front matter alias `description` for `summary`
  - Created a new helper function: get_summary.html
  - Implements the priority order: .Params.summary > .Params.description > .Params.abstract > .Summary.
- clamp abstract in date-title-summary view
- default gradient mesh block bg to primary-secondary gradient from theme pack
- improve inline code styling - remove backticks around code

BREAKING CHANGE:
`params.yaml` data structure has changed - see docs and latest templates for example

modules/blox-tailwind/assets/css/framework/base.css

@@ -89,4 +89,15 @@
     background-color: var(--color-primary-400);
     color: black;
   }
+
+  /* Inline Code Styling */
+  .prose code:not(:where(pre *)) {
+    @apply rounded-md bg-neutral-100 px-1.5 py-0.5 text-[0.875em] font-normal text-primary-700;
+    @apply dark:bg-neutral-700/50 dark:text-primary-300;
+  }
+
+  .prose code:not(:where(pre *))::before,
+  .prose code:not(:where(pre *))::after {
+    content: none !important;
+  }
 }