Switch search runtime to vendored sqlite3 WASM

vendor/sqlite3/README.txt

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+This is the README for the sqlite3 WASM/JS distribution.
+
+Main project page: https://sqlite.org
+
+Documentation: https://sqlite.org/wasm
+
+This archive contains the following deliverables for the WASM/JS
+build:
+
+- jswasm/sqlite3.js is the canonical "vanilla JS" version.
+
+- jswasm/sqlite3.mjs is the same but in ES6 module form
+
+- jswasm/*-bundler-friendly.js and .mjs are variants which are
+  intended to be compatible with "bundler" tools commonly seen in
+  node.js-based projects. Projects using such tools should use those
+  variants, where available, instead of files without the
+  "-bundler-friendly" suffix. Some files do not have separate
+  variants.
+
+- jswasm/sqlite3.wasm is the binary WASM file imported by all of the
+  above-listed JS files.
+
+- The jswasm directory additionally contains a number of supplemental
+  JS files which cannot be bundled directly with the main JS files
+  but are necessary for certain usages.
+
+- The top-level directory contains various demonstration and test
+  applications for sqlite3.js and sqlite3.mjs.
+  sqlite3-bundler-friendly.mjs requires client-side build tools to make
+  use of and is not demonstrated here.
+
+Browsers will not serve WASM files from file:// URLs, so the test and
+demonstration apps require a web server and that server must include
+the following headers in its response when serving the files:
+
+    Cross-Origin-Opener-Policy: same-origin
+    Cross-Origin-Embedder-Policy: require-corp
+
+The core library will function without those headers but certain
+features, most notably OPFS storage, will not be available.
+
+One simple way to get the demo apps up and running on Unix-style
+systems is to install althttpd (https://sqlite.org/althttpd) and run:
+
+    althttpd --enable-sab --page index.html