refactor: harden type safety and modernize core forms for Svelte 5

- Standardize 'ae_BaseObj' and event types in 'ae_types.ts' to handle nullable fields from V3 API/Dexie.
- Modernize Person, Address, and Contact forms with Svelte 5 Runes and reactive synchronization.
- Refactor Event Settings and its sub-components to use the 'onsave' callback pattern, removing deprecated dispatchers.
- Hardened 'element_data_store_v2' with safe initialization and localStorage caching logic.
- Clean up unused 'element_data_store.svelte' (V1) and suppress Electron environment type errors in 'tmp_shell_handlers.ts'.
- Update documentation and workspace settings to reflect Phase 5 reactive patterns.

aether_app_sveltekit.code-workspace

@@ -5,7 +5,10 @@
         }
     ],
     "settings": {
-        "cSpell.words": ["filelist"],
+        "cSpell.words": [
+            "filelist",
+            "onsave"
+        ],
         "git.autofetch": true,
         "editor.defaultFormatter": "svelte.svelte-vscode"
     }