Close the retention follow-ups from the August review (closes #99)

Follow-ups from an August review of the retention bounds, each checked against the current tree. A test now pins that a retention value above the keep-forever sentinel is stored as the sentinel. The form's retention parser returns its message directly, so the two error values that were never compared, and the function that mapped them to messages, are gone. The sweep's own keep-forever skip, which duplicated the check in retentionCutoff, is removed; the cutoff is now asked before the webhook's database is opened. The create-form refill test uses HTML-special characters and checks they come back escaped. The README item was already settled; handling for rows made by hand is declined.

Model: opus-5-5

internal/handlers/source_management_test.go

@@ -368,31 +368,42 @@ func TestHandleSourceCreateSubmit_OverflowingRetentionIsRejected(
 // boundary between "too large to represent" and "retain forever": the
 // sentinel is above MaxFiniteRetentionDays, but it is the value the
 // edit form pre-fills, so it must be accepted rather than rejected as
-// out of range.
+// out of range. A value above the sentinel is stored as the sentinel.
 func TestHandleSourceCreateSubmit_SentinelIsAcceptedAsForever(
 	t *testing.T,
 ) {
 	t.Parallel()
 
-	env := setupSourceTest(t)
-	sentinel := strconv.Itoa(database.RetentionForeverDays)
-
-	w := submitCreate(t, env.handlers, env.cookies, "forever", &sentinel)
-	require.Equal(t, http.StatusSeeOther, w.Code)
-
-	wh := onlyWebhook(t, env.db)
-	assert.Equal(
-		t,
+	for _, days := range []int{
 		database.RetentionForeverDays,
-		storedRetentionDays(t, env.db, wh.ID),
-	)
+		database.RetentionForeverDays + 1,
+	} {
+		raw := strconv.Itoa(days)
+
+		t.Run(raw, func(t *testing.T) {
+			t.Parallel()
+
+			env := setupSourceTest(t)
+
+			w := submitCreate(t, env.handlers, env.cookies, "forever", &raw)
+			require.Equal(t, http.StatusSeeOther, w.Code)
+
+			wh := onlyWebhook(t, env.db)
+			assert.Equal(
+				t,
+				database.RetentionForeverDays,
+				storedRetentionDays(t, env.db, wh.ID),
+			)
+		})
+	}
 }
 
 // TestHandleSourceCreateSubmit_RejectedFormKeepsUserInput checks that a
 // validation failure hands the user's typing back, matching what the
 // edit form already does. Losing a long description to a mistyped
 // retention value is the kind of thing that makes people give up on a
-// form.
+// form. Both values carry HTML-special characters, which must come
+// back escaped rather than as markup.
 func TestHandleSourceCreateSubmit_RejectedFormKeepsUserInput(
 	t *testing.T,
 ) {
@@ -401,8 +412,8 @@ func TestHandleSourceCreateSubmit_RejectedFormKeepsUserInput(
 	env := setupSourceTest(t)
 
 	const (
-		name        = "kept-name"
-		description = "a description worth not losing"
+		name        = `kept"><b>name`
+		description = `a </textarea> worth not losing`
 	)
 
 	form := url.Values{}
@@ -419,8 +430,10 @@ func TestHandleSourceCreateSubmit_RejectedFormKeepsUserInput(
 
 	body := w.Body.String()
 
-	assert.Contains(t, body, `value="`+name+`"`)
-	assert.Contains(t, body, description)
+	assert.Contains(t, body, `value="kept&#34;&gt;&lt;b&gt;name"`)
+	assert.Contains(t, body, `a &lt;/textarea&gt; worth not losing`)
+	assert.NotContains(t, body, name)
+	assert.NotContains(t, body, description)
 }
 
 // submitEdit posts the webhook edit form for the given webhook.