fix(dkv): fix EWS attachment ID extraction — FileAttachment has no Id attribute

extractAttrs(block, 't:FileAttachment', 'Id') always returned empty array
because the attachment Id lives in a child <t:AttachmentId Id="..."/>, not
on the <t:FileAttachment> tag itself. This caused all Exchange inbox checks
to silently find zero PDF attachments and report "no matching emails".

Fixed by iterating FileAttachment blocks individually and extracting
t:AttachmentId/@Id from within each block. Also added filename (.pdf)
as fallback when ContentType is application/octet-stream.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/api/src/dkv/providers/exchange-inbox.provider.ts

@@ -272,12 +272,27 @@ export class ExchangeInboxProvider implements InboxProvider {
           continue;
         }
 
-        // Collect PDF attachment IDs
-        const attachmentIds = extractAttrs(block, 't:FileAttachment', 'Id')
-          .filter((_, idx) => {
-            const types = extractAll(block, 't:ContentType');
-            return (types[idx] ?? '').toLowerCase().includes('pdf');
-          });
+        // Collect PDF attachment IDs by iterating each FileAttachment block.
+        // extractAttrs(block, 't:FileAttachment', 'Id') was wrong — the Id lives
+        // inside a child <t:AttachmentId Id="..."/> not on the FileAttachment tag.
+        const attachmentIds: string[] = [];
+        const FA_OPEN = '<t:FileAttachment>';
+        const FA_CLOSE = '</t:FileAttachment>';
+        let faPos = 0;
+        while (faPos < block.length) {
+          const faStart = block.indexOf(FA_OPEN, faPos);
+          if (faStart === -1) break;
+          const faEnd = block.indexOf(FA_CLOSE, faStart);
+          if (faEnd === -1) break;
+          const faBlock = block.slice(faStart, faEnd);
+          const attId = extractAttr(faBlock, 't:AttachmentId', 'Id');
+          const ct = (extractAll(faBlock, 't:ContentType')[0] ?? '').toLowerCase();
+          const nm = (extractAll(faBlock, 't:Name')[0] ?? '').toLowerCase();
+          if (attId && (ct.includes('pdf') || nm.endsWith('.pdf'))) {
+            attachmentIds.push(attId);
+          }
+          faPos = faEnd + FA_CLOSE.length;
+        }
 
         if (attachmentIds.length === 0) continue;