feat: webhook payload history — store and display recent incoming payloads

Backend:
- WebhookPayloadLog model (provider_id, method, headers, body, status, extracted_fields, error_message)
- Auto-log payloads in generic_webhook() with matched/unmatched/error status
- Auto-prune beyond max_stored_payloads per provider
- Header filtering (only Content-Type, User-Agent, X-* stored; no Authorization)
- GET/DELETE /api/providers/{id}/webhook-logs endpoints
- store_payloads + max_stored_payloads in WebhookProviderConfig

Frontend:
- WebhookPayloadHistory.svelte — expandable log viewer with status badges, JSON body, headers, extracted fields
- payloadHistory flag on webhook provider descriptor
- max_stored_payloads config field (0 = disabled)
- Password confirmation field on change password modal
- i18n keys for webhook logs (en + ru)

frontend/src/routes/+layout.svelte

@@ -59,19 +59,21 @@
 	let openSearch: (() => void) | undefined;
 	let pwdCurrent = $state('');
 	let pwdNew = $state('');
+	let pwdConfirm = $state('');
 	let pwdMsg = $state('');
 	let pwdSuccess = $state(false);
 
 	async function changePassword(e: SubmitEvent) {
 		e.preventDefault(); pwdMsg = ''; pwdSuccess = false;
 		if (pwdNew.length < 8) { pwdMsg = t('auth.passwordTooShort'); return; }
+		if (pwdNew !== pwdConfirm) { pwdMsg = t('auth.passwordMismatch'); return; }
 		try {
 			await api('/auth/password', { method: 'PUT', body: JSON.stringify({ current_password: pwdCurrent, new_password: pwdNew }) });
 			pwdMsg = t('common.changePassword');
 			pwdSuccess = true;
-			pwdCurrent = ''; pwdNew = '';
+			pwdCurrent = ''; pwdNew = ''; pwdConfirm = '';
 			snackSuccess(t('snack.passwordChanged'));
-			setTimeout(() => { showPasswordForm = false; pwdMsg = ''; pwdSuccess = false; }, 2000);
+			setTimeout(() => { showPasswordForm = false; pwdMsg = ''; pwdSuccess = false; pwdConfirm = ''; }, 2000);
 		} catch (err: any) { pwdMsg = err.message; pwdSuccess = false; snackError(err.message); }
 	}
 
@@ -605,7 +607,7 @@
 {/if}
 
 <!-- Password change modal -->
-<Modal open={showPasswordForm} title={t('common.changePassword')} onclose={() => { showPasswordForm = false; pwdMsg = ''; pwdSuccess = false; }}>
+<Modal open={showPasswordForm} title={t('common.changePassword')} onclose={() => { showPasswordForm = false; pwdMsg = ''; pwdSuccess = false; pwdConfirm = ''; }}>
 	<form onsubmit={changePassword} class="space-y-3">
 		<div>
 			<label for="pwd-current" class="block text-sm font-medium mb-1">{t('common.currentPassword')}</label>
@@ -614,7 +616,12 @@
 		</div>
 		<div>
 			<label for="pwd-new" class="block text-sm font-medium mb-1">{t('common.newPassword')}</label>
-			<input id="pwd-new" type="password" bind:value={pwdNew} required
+			<input id="pwd-new" type="password" bind:value={pwdNew} required minlength="8"
+				class="w-full px-3 py-2 border border-[var(--color-border)] rounded-lg text-sm bg-[var(--color-background)]" />
+		</div>
+		<div>
+			<label for="pwd-confirm" class="block text-sm font-medium mb-1">{t('auth.confirmPassword')}</label>
+			<input id="pwd-confirm" type="password" bind:value={pwdConfirm} required minlength="8"
 				class="w-full px-3 py-2 border border-[var(--color-border)] rounded-lg text-sm bg-[var(--color-background)]" />
 		</div>
 		{#if pwdMsg}