feat: replace all primary (blue) with contextual colors across entire theme

Eliminate monotonous blue by replacing ~290 primary- references in 60 files
with semantically appropriate colors:

- accent (teal): links, CTAs, buttons, tabs, focus rings, spinners
- purple: Funkwhale/music, photos, Mastodon/fediverse
- surface (neutral): GitHub, dates/metadata, info boxes
- amber: bookmarks, blogroll categories
- red: likes
- green: reposts
- sky: replies
- orange: RSS/feeds, podcasts
- #0085ff: Bluesky brand
- #a730b8: Mastodon brand

Also updates prose link colors in tailwind.config.js, pagefind UI
primary color to teal, and client-side JS color references.

Confab-Link: http://localhost:8080/sessions/bd3f7012-c703-47e9-bfe2-2ad04ce1842d

tailwind.config.js

@@ -78,13 +78,13 @@ export default {
       typography: (theme) => ({
         DEFAULT: {
           css: {
-            "--tw-prose-links": theme("colors.primary.600"),
+            "--tw-prose-links": theme("colors.accent.600"),
             maxWidth: "none",
           },
         },
         invert: {
           css: {
-            "--tw-prose-links": theme("colors.primary.400"),
+            "--tw-prose-links": theme("colors.accent.400"),
           },
         },
       }),