add tree-sitter syntax highlighting via dart:ffi

Vendor libtree-sitter.so (v0.26.8, wasmtime 44.0 statically linked)
and call its C API through dart:ffi. Grammar WASM files are loaded by
tree-sitter's embedded wasmtime engine via ts_wasm_store_load_language.

48 grammars compiled with tree-sitter build --wasm, 48 highlight
queries (42 from upstream repos, 6 written in-house for comment,
erlang, gdscript, gitignore, hcl, hlsl, swift). SQLite grammar
replaces full SQL (974K-line parser exhausted RAM at compile time).

Removes wasm_run and wasm_run_flutter — they downloaded a 22 MB
binary from GitHub at first launch, violating the no-network-on-
default-launch-path policy.

Co-Authored-By: Claude <noreply@anthropic.com>

app/linux/CMakeLists.txt

@@ -112,6 +112,12 @@ install(DIRECTORY "${NATIVE_ASSETS_DIR}"
    DESTINATION "${INSTALL_BUNDLE_LIB_DIR}"
    COMPONENT Runtime)
 
+# Vendored native libraries (libtree-sitter with wasmtime embedded).
+install(DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}/../native/linux-x64/"
+  DESTINATION "${INSTALL_BUNDLE_LIB_DIR}"
+  COMPONENT Runtime
+  FILES_MATCHING PATTERN "*.so")
+
 # Fully re-copy the assets directory on each build to avoid having stale files
 # from a previous install.
 set(FLUTTER_ASSET_DIR_NAME "flutter_assets")