Split web/ into senbei-wasm crate + static assets

The Rust bindings move from web/src to a top-level senbei-wasm crate (still
outside the workspace, own Cargo.lock), matching the other senbei-* crates.
web/ keeps only the static frontend; wasm-pack emits the JS/wasm package into
web/pkg/ via --out-dir. JS glue renamed senbei_web -> senbei_wasm with the
crate.

senbei-wasm/Cargo.toml

@@ -0,0 +1,21 @@
+[package]
+name = "senbei-wasm"
+version = "1.1.0"
+edition = "2024"
+description = "WebAssembly bindings for senbei (browser frontend assets live in web/)"
+license = "AGPL-3.0-only"
+
+[lib]
+crate-type = ["cdylib"]
+
+[dependencies]
+senbei-io = { path = "../senbei-io" }
+senbei-metadata = { path = "../senbei-metadata" }
+senbei-pe = { path = "../senbei-pe" }
+wasm-bindgen = "0.2"
+console_error_panic_hook = "0.1"
+
+[profile.release]
+opt-level = "z"
+lto = true
+codegen-units = 1