Enable brotli compression for API and static files

- Add compression-br feature to tower-http
- Apply CompressionLayer to API routes (JSON responses)
- Apply CompressionLayer to static files (CSS, JS, locales)
- File downloads remain uncompressed (avoid double compression)

Cargo.lock

@@ -28,6 +28,21 @@ dependencies = [
  "memchr",
 ]
 
+[[package]]
+name = "alloc-no-stdlib"
+version = "2.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cc7bb162ec39d46ab1ca8c77bf72e890535becd1751bb45f64c597edb4c8c6b3"
+
+[[package]]
+name = "alloc-stdlib"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "94fb8275041c72129eb51b7d0322c29b8387a0386127718b096429201a5d6ece"
+dependencies = [
+ "alloc-no-stdlib",
+]
+
 [[package]]
 name = "allocator-api2"
 version = "0.2.21"
@@ -263,6 +278,27 @@ dependencies = [
  "generic-array",
 ]
 
+[[package]]
+name = "brotli"
+version = "8.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4bd8b9603c7aa97359dbd97ecf258968c95f3adddd6db2f7e7a5bef101c84560"
+dependencies = [
+ "alloc-no-stdlib",
+ "alloc-stdlib",
+ "brotli-decompressor",
+]
+
+[[package]]
+name = "brotli-decompressor"
+version = "5.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "874bb8112abecc98cbd6d81ea4fa7e94fb9449648c93cc89aa40c81c24d7de03"
+dependencies = [
+ "alloc-no-stdlib",
+ "alloc-stdlib",
+]
+
 [[package]]
 name = "bumpalo"
 version = "3.19.1"
@@ -362,6 +398,7 @@ version = "0.4.36"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "00828ba6fd27b45a448e57dbfe84f1029d4c9f26b368157e9a448a5f49a2ec2a"
 dependencies = [
+ "brotli",
  "compression-core",
  "flate2",
  "memchr",