Send Email and Mark Sent modals for invoices and quotes (db 2.7.7)

Send Email opens a contact picker instead of hardcoding the primary contact; Mark Sent asks how it went out and takes a note. Both log recipients / method / note to the document history. Handlers moved GET -> POST.

Fixes two pre-existing bugs in the email path: archived contacts were still receiving billing copies, and every copy was addressed to the primary contact by name.

agent/modals/quote/quote_mark_sent.php

@@ -0,0 +1,64 @@
+<?php
+
+require_once '../../../includes/modal_header.php';
+
+enforceUserPermission('module_sales', 2);
+
+$quote_id = intval($_GET['quote_id']);
+
+$sql = mysqli_query($mysqli, "SELECT quote_client_id, quote_number, quote_prefix
+    FROM quotes WHERE quote_id = $quote_id LIMIT 1");
+$row = mysqli_fetch_assoc($sql);
+$quote_prefix = escapeHtml($row['quote_prefix']);
+$quote_number = intval($row['quote_number']);
+$client_id = intval($row['quote_client_id']);
+
+enforceClientAccess();
+
+ob_start();
+
+?>
+
+<div class="modal-header bg-dark">
+    <h5 class="modal-title text-white">
+        <i class="fa fa-fw fa-check me-2"></i>Mark Quote <?= "$quote_prefix$quote_number" ?> Sent
+    </h5>
+    <button type="button" class="btn-close btn-close-white" data-bs-dismiss="modal"></button>
+</div>
+<form action="post.php" method="post" autocomplete="off">
+    <input type="hidden" name="csrf_token" value="<?= $_SESSION['csrf_token'] ?>">
+    <input type="hidden" name="quote_id" value="<?= $quote_id ?>">
+
+    <div class="modal-body">
+
+        <div class="mb-3">
+            <label>How was it sent? <strong class="text-danger">*</strong></label>
+            <div class="input-group">
+                <span class="input-group-text"><i class="fa fa-fw fa-paper-plane"></i></span>
+                <select class="form-select" name="sent_method" required>
+                    <?php foreach (getSentMethods() as $sent_method) { ?>
+                        <option value="<?= escapeHtml($sent_method) ?>"><?= escapeHtml($sent_method) ?></option>
+                    <?php } ?>
+                </select>
+            </div>
+        </div>
+
+        <div class="mb-3">
+            <label>Note</label>
+            <textarea class="form-control" name="note" rows="3" maxlength="500"
+                placeholder="Optional - tracking number, who it went to, anything worth keeping"></textarea>
+        </div>
+
+    </div>
+    <div class="modal-footer">
+        <button type="submit" name="mark_quote_sent" class="btn btn-primary text-bold">
+            <i class="fa fa-fw fa-check me-2"></i>Mark Sent
+        </button>
+        <button type="button" class="btn btn-light" data-bs-dismiss="modal">
+            <i class="fa fa-fw fa-times me-2"></i>Cancel
+        </button>
+    </div>
+</form>
+
+<?php
+require_once '../../../includes/modal_footer.php';