feat(journals): extract decryption logic to helper and improve Quick Add behavior

- Extracted journal entry decryption workflow to 'ae_journals_decryption.ts' to decouple it from Svelte reactivity and address loop issues.
- Updated 'ae_comp__journal_entry_obj_id_view.svelte' to use the new decryption helper.
- Refactored 'Quick Add' to use the first line as the title and remove it from the content before saving.

src/lib/ae_journals/ae_journals_decryption.ts

@@ -0,0 +1,90 @@
+import { ae_util } from '$lib/ae_utils/ae_utils';
+import type { ae_JournalEntry, ae_Journal } from '$lib/types/ae_types';
+
+/**
+ * Result structure for decryption operations.
+ */
+export interface DecryptionResult {
+    success: boolean;
+    content?: string;
+    history?: string;
+    error?: string;
+}
+
+/**
+ * Decrypts a journal entry's content and history using the provided or stored passcode.
+ * 
+ * @param entry The journal entry object to decrypt.
+ * @param journal The parent journal object (provides base passcode and private_passcode).
+ * @param typed_passcode Optional: A user-entered passcode override.
+ * @returns A Promise resolving to a DecryptionResult.
+ */
+export async function decrypt_journal_entry(
+    entry: ae_JournalEntry,
+    journal: ae_Journal,
+    typed_passcode?: string
+): Promise<DecryptionResult> {
+    
+    // Safety check: if not encrypted, return as-is
+    if (!entry.content_encrypted) {
+        return { 
+            success: true, 
+            content: entry.content ?? '',
+            history: entry.history ?? ''
+        };
+    }
+
+    // Determine which key to use
+    let journal_key = typed_passcode;
+    
+    // If no override, try the private passcode stored on the journal object
+    if (!journal_key?.length) {
+        journal_key = journal.private_passcode;
+    }
+    
+    if (!journal_key) {
+        return { 
+            success: false, 
+            error: 'No passcode provided or available for decryption.' 
+        };
+    }
+
+    // Aether standard: combine the journal's public passcode with the private key
+    const decrypt_key = `${journal.passcode ?? ''}:${journal_key}`;
+
+    try {
+        // Decrypt Primary Content
+        const result = await ae_util.decrypt_wrapper(entry.content_encrypted, decrypt_key);
+
+        if (result === false) {
+            return { 
+                success: false, 
+                error: 'Decryption failed. Incorrect passcode or corrupted data.' 
+            };
+        }
+
+        const decrypted_text = typeof result === 'string' ? result : '';
+        let decrypted_history = '';
+
+        // Decrypt History (if it exists)
+        if (entry.history_encrypted) {
+            const h_res = await ae_util.decrypt_wrapper(entry.history_encrypted, decrypt_key);
+            if (h_res !== false) {
+                decrypted_history = typeof h_res === 'string' ? h_res : '';
+            }
+        }
+
+        return { 
+            success: true, 
+            content: decrypted_text,
+            history: decrypted_history
+        };
+
+    } catch (err: any) {
+        console.error('decrypt_journal_entry error:', err);
+        return { 
+            success: false, 
+            error: `System error during decryption: ${err.message}` 
+        };
+    }
+}