Switch indexeddb backend to sqlite and improve IPC messaging (#38187)

- Use sqlite instead of heed. (one indexed database = one sqlite
database)
- Implement the backend for indexes
- Use keyranges where needed (as specified by the spec)
- Implement `getKey`
- Fix channel error messaging (led to a bunch of changes to how async
requests are handled)

Note: `components/net/indexeddb/engines/sqlite/serialize.rs` is unused;
I can delete it if needed.

Testing: Switching to sqlite eliminated many panics (exposing some new
failures).
Fixes: #38040

---------

Signed-off-by: Ashwin Naren <arihant2math@gmail.com>

components/net/indexeddb/engines/sqlite/database_model.rs

@@ -0,0 +1,22 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+use sea_query::Iden;
+
+#[derive(Iden)]
+#[expect(unused)]
+pub enum Column {
+    Table,
+    Name,
+    Origin,
+    Version,
+}
+
+#[derive(Clone, Debug, Eq, PartialEq)]
+pub struct Model {
+    pub name: String,
+    pub origin: String,
+    pub version: i64,
+    // TODO: Hold timestamp for vacuuming
+    // TODO: implement vacuuming
+}