fix(ssr): resolve EventSource SSR violations and implement best practices

- Fix EventSource is not defined error in queue dashboard
- Add browser guards for all EventSource usage
- Replace static constants (EventSource.OPEN/CLOSED) with numeric values
- Fix setInterval SSR violation in LLM health indicator
- Replace $effect anti-pattern with onMount in share page
- Add comprehensive SvelteKit SSR best practices documentation
- Add SSR audit and testing verification

All changes follow SvelteKit best practices and are verified against
official documentation. Production build succeeds with no SSR errors.

Closes: FixEventSourceSSR
See: docs/outcomes/FixEventSourceSSR.md

package.json

@@ -43,8 +43,11 @@
         "vitest-browser-svelte": "^2.0.1"
     },
     "dependencies": {
+        "@types/uuid": "^10.0.0",
+        "date-fns": "^4.1.0",
         "openai": "^4.20.0",
         "playwright": "^1.56.1",
+        "uuid": "^13.0.0",
         "zod": "^3.23.0"
     }
 }