feat(dictionary): add Hachidori backend support

- Add backend selection, setup gating, Anki integration, and external host support
- Add launcher flags, documentation, packaging, and focused tests
- Open on-demand overlay modals on the first attempt

vendor/hachidori/wasm/build.sh

@@ -0,0 +1,52 @@
+#!/bin/sh
+# Builds the threaded OPFS runtime, the threaded IDBFS runtime for hosts without
+# OPFS access handles, and the single-thread IDBFS fallback.
+set -e
+
+WASM_DIR=$(CDPATH= cd -- "$(dirname -- "$0")" && pwd)
+REPO_ROOT=$(CDPATH= cd -- "$WASM_DIR/.." && pwd)
+THREADED_BUILD_DIR="${BUILD_DIR:-$WASM_DIR/build}"
+THREADED_IDBFS_BUILD_DIR="${THREADED_IDBFS_BUILD_DIR:-${THREADED_BUILD_DIR}-idbfs}"
+FALLBACK_BUILD_DIR="${FALLBACK_BUILD_DIR:-${THREADED_BUILD_DIR}-fallback}"
+VENDOR_DIR="$REPO_ROOT/extension/vendor"
+
+# shellcheck disable=SC1091
+. "$WASM_DIR/env.sh"
+
+build_runtime() {
+  build_dir=$1
+  pthreads=$2
+  wasmfs=$3
+  emcmake cmake -S "$WASM_DIR" -B "$build_dir" \
+    -DCMAKE_BUILD_TYPE=Release \
+    -DHACHIDORI_PTHREADS="$pthreads" \
+    -DHACHIDORI_WASMFS="$wasmfs"
+  cmake --build "$build_dir" --parallel "$(nproc 2>/dev/null || printf '%s\n' 4)"
+}
+
+build_runtime "$THREADED_BUILD_DIR" ON ON
+build_runtime "$THREADED_IDBFS_BUILD_DIR" ON OFF
+build_runtime "$FALLBACK_BUILD_DIR" OFF ON
+
+mkdir -p "$VENDOR_DIR"
+cp "$THREADED_BUILD_DIR/hoshidicts-threaded.mjs" "$VENDOR_DIR/hoshidicts-threaded.mjs"
+cp "$THREADED_BUILD_DIR/hoshidicts-threaded.wasm" "$VENDOR_DIR/hoshidicts-threaded.wasm"
+cp "$THREADED_IDBFS_BUILD_DIR/hoshidicts-threaded-idbfs.mjs" "$VENDOR_DIR/hoshidicts-threaded-idbfs.mjs"
+cp "$THREADED_IDBFS_BUILD_DIR/hoshidicts-threaded-idbfs.wasm" "$VENDOR_DIR/hoshidicts-threaded-idbfs.wasm"
+cp "$FALLBACK_BUILD_DIR/hoshidicts.mjs" "$VENDOR_DIR/hoshidicts.mjs"
+cp "$FALLBACK_BUILD_DIR/hoshidicts.wasm" "$VENDOR_DIR/hoshidicts.wasm"
+chmod 644 \
+  "$VENDOR_DIR/hoshidicts-threaded.mjs" \
+  "$VENDOR_DIR/hoshidicts-threaded.wasm" \
+  "$VENDOR_DIR/hoshidicts-threaded-idbfs.mjs" \
+  "$VENDOR_DIR/hoshidicts-threaded-idbfs.wasm" \
+  "$VENDOR_DIR/hoshidicts.mjs" \
+  "$VENDOR_DIR/hoshidicts.wasm"
+
+ls -l \
+  "$VENDOR_DIR/hoshidicts-threaded.mjs" \
+  "$VENDOR_DIR/hoshidicts-threaded.wasm" \
+  "$VENDOR_DIR/hoshidicts-threaded-idbfs.mjs" \
+  "$VENDOR_DIR/hoshidicts-threaded-idbfs.wasm" \
+  "$VENDOR_DIR/hoshidicts.mjs" \
+  "$VENDOR_DIR/hoshidicts.wasm"