perf(core): standardize non-blocking load pattern and add performance guidelines

- Documented the 'Non-Blocking Load Pattern' (SWR) in 'documentation/PERFORMANCE_GUIDELINES.md' to prevent future performance regressions.
- Refactored 'src/routes/core/people/[person_id]/+page.ts' to be non-blocking, improving perceived speed for person details.
- Updated 'GEMINI.md' standards and 'TODO.md' tasks to reflect system-wide performance hardening.

src/routes/core/people/[person_id]/+page.ts

@@ -1,5 +1,6 @@
 /** @type {import('./$types').PageLoad} */
 import { error } from '@sveltejs/kit';
+import { browser } from '$app/environment';
 console.log(`ae core person [person_id] +page.ts: start`);
 
 import { core_func } from '$lib/ae_core/ae_core_functions';
@@ -18,10 +19,10 @@ export async function load({ params, parent }) {
     const ae_acct = { ...data[account_id] };
     ae_acct.slct = { ...ae_acct.slct };
     
-    console.log(`ae_acct = `, ae_acct);
+    // console.log(`ae_acct = `, ae_acct);
 
     const person_id = params.person_id;
-    console.log(`person_id = `, person_id);
+    // console.log(`person_id = `, person_id);
     if (!person_id) {
         console.log(
             `ae core person [person_id] +page.ts: The person_id was not found in the params!!!`
@@ -33,13 +34,16 @@ export async function load({ params, parent }) {
 
     ae_acct.slct.person_id = person_id;
 
-    const load_person_obj = await core_func.load_ae_obj_id__person({
-        api_cfg: ae_acct.api,
-        person_id: person_id,
-        try_cache: true
-    });
-
-    ae_acct.slct.person_obj = load_person_obj;
+    if (browser) {
+        // OPTIMIZATION: Fire the refresh in the background.
+        // The Person View UI uses LiveQuery/Dexie and will update 
+        // automatically once this background task finishes.
+        core_func.load_ae_obj_id__person({
+            api_cfg: ae_acct.api,
+            person_id: person_id,
+            try_cache: true
+        });
+    }
 
     return {
         ...data,