fix: replace broken DashMap rate limiting with tower-governor middleware

- Replace custom DashMap<IpAddr, Instant> rate limiting in enrollment.rs
  that fell back to 0.0.0.0 when X-Forwarded-For was missing, causing
  ALL enrollment traffic to share a single global rate limit bucket
- Use tower_governor with SmartIpKeyExtractor for proper per-IP rate
  limiting that respects X-Forwarded-For headers (critical behind HAProxy)
- Add three configurable rate limit tiers via config.toml:
  * Enrollment: 5 req/min per IP, burst 3 (strict)
  * Auth: 20 req/min per IP, burst 10 (moderate)
  * API: 120 req/min per IP, burst 30 (normal)
- Remove enrollment_rate_limits from AppState and cleanup task
- Remove manual rate limit code from enrollment.rs (headers param, IP extraction)
- Add into_make_service_with_connect_info for ConnectInfo fallback
- Add RateLimitConfig to AppConfig with sensible defaults

Fixes: #1

Cargo.lock

@@ -687,6 +687,19 @@ dependencies = [
  "cipher",
 ]
 
+[[package]]
+name = "dashmap"
+version = "5.5.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "978747c1d849a7d2ee5e8adc0159961c48fb7e5db2f06af6723b80123bb53856"
+dependencies = [
+ "cfg-if",
+ "hashbrown 0.14.5",
+ "lock_api",
+ "once_cell",
+ "parking_lot_core",
+]
+
 [[package]]
 name = "dashmap"
 version = "6.1.0"
@@ -771,7 +784,7 @@ dependencies = [
  "libc",
  "option-ext",
  "redox_users",
- "windows-sys 0.60.2",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -885,7 +898,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "39cab71617ae0d63f51a36d69f866391735b51691dbda63cf6f96d042b63efeb"
 dependencies = [
  "libc",
- "windows-sys 0.60.2",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -970,6 +983,12 @@ version = "0.1.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d9c4f5dac5e15c24eb999c26181a6ca40b39fe946cbe4c263c7209467bc83af2"
 
+[[package]]
+name = "foldhash"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "77ce24cb58228fbb8aa041425bb1050850ac19177686ea6e0f41a70416f56fdb"
+
 [[package]]
 name = "font-kit"
 version = "0.14.3"
@@ -1046,6 +1065,16 @@ dependencies = [
  "percent-encoding",
 ]
 
+[[package]]
+name = "forwarded-header-value"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8835f84f38484cc86f110a805655697908257fb9a7af005234060891557198e9"
+dependencies = [
+ "nonempty",
+ "thiserror 1.0.69",
+]
+
 [[package]]
 name = "freetype-sys"
 version = "0.20.1"
@@ -1155,6 +1184,12 @@ version = "0.3.32"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "037711b3d59c33004d3856fbdc83b99d4ff37a24768fa1be9ce3538a1cde4393"
 
+[[package]]
+name = "futures-timer"
+version = "3.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "af43fadb8a98512d547e37b4e92e0ced13e205c061b87b4623eff01d918d6968"
+
 [[package]]
 name = "futures-util"
 version = "0.3.32"
@@ -1242,6 +1277,49 @@ dependencies = [
  "weezl",
 ]
 
+[[package]]
+name = "governor"
+version = "0.6.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "68a7f542ee6b35af73b06abc0dad1c1bae89964e4e253bc4b587b91c9637867b"
+dependencies = [
+ "cfg-if",
+ "dashmap 5.5.3",
+ "futures",
+ "futures-timer",
+ "no-std-compat",
+ "nonzero_ext",
+ "parking_lot",
+ "portable-atomic",
+ "quanta",
+ "rand 0.8.6",
+ "smallvec",
+ "spinning_top",
+]
+
+[[package]]
+name = "governor"
+version = "0.10.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9efcab3c1958580ff1f25a2a41be1668f7603d849bb63af523b208a3cc1223b8"
+dependencies = [
+ "cfg-if",
+ "dashmap 6.1.0",
+ "futures-sink",
+ "futures-timer",
+ "futures-util",
+ "getrandom 0.3.4",
+ "hashbrown 0.16.1",
+ "nonzero_ext",
+ "parking_lot",
+ "portable-atomic",
+ "quanta",
+ "rand 0.9.4",
+ "smallvec",
+ "spinning_top",
+ "web-time",
+]
+
 [[package]]
 name = "h2"
 version = "0.4.13"
@@ -1275,7 +1353,18 @@ checksum = "9229cfe53dfd69f0609a49f65461bd93001ea1ef889cd5529dd176593f5338a1"
 dependencies = [
  "allocator-api2",
  "equivalent",
- "foldhash",
+ "foldhash 0.1.5",
+]
+
+[[package]]
+name = "hashbrown"
+version = "0.16.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "841d1cc9bed7f9236f321df977030373f4a4163ae1a7dbfe1a51a2c1a51d9100"
+dependencies = [
+ "allocator-api2",
+ "equivalent",
+ "foldhash 0.2.0",
 ]
 
 [[package]]
@@ -1445,6 +1534,19 @@ dependencies = [
  "webpki-roots 1.0.7",
 ]
 
+[[package]]
+name = "hyper-timeout"
+version = "0.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2b90d566bffbce6a75bd8b09a05aa8c2cb1fabb6cb348f8840c9e4c90a0d83b0"
+dependencies = [
+ "hyper",
+ "hyper-util",
+ "pin-project-lite",
+ "tokio",
+ "tower-service",
+]
+
 [[package]]
 name = "hyper-tls"
 version = "0.6.0"
@@ -1994,6 +2096,12 @@ dependencies = [
  "tempfile",
 ]
 
+[[package]]
+name = "no-std-compat"
+version = "0.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b93853da6d84c2e3c7d730d6473e8817692dd89be387eb01b94d7f108ecb5b8c"
+
 [[package]]
 name = "nom"
 version = "7.1.3"
@@ -2013,13 +2121,25 @@ dependencies = [
  "memchr",
 ]
 
+[[package]]
+name = "nonempty"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e9e591e719385e6ebaeb5ce5d3887f7d5676fceca6411d1925ccc95745f3d6f7"
+
+[[package]]
+name = "nonzero_ext"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "38bf9645c8b145698bb0b18a4637dcacbc421ea49bef2317e4fd8065a387cf21"
+
 [[package]]
 name = "nu-ansi-term"
 version = "0.50.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7957b9740744892f114936ab4a57b3f487491bbeafaf8083688b16841a4240e5"
 dependencies = [
- "windows-sys 0.60.2",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -2307,6 +2427,26 @@ dependencies = [
  "sha2",
 ]
 
+[[package]]
+name = "pin-project"
+version = "1.1.13"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2466b2336ed02bcdca6b294417127b90ec92038d1d5c4fbeac971a922e0e0924"
+dependencies = [
+ "pin-project-internal",
+]
+
+[[package]]
+name = "pin-project-internal"
+version = "1.1.13"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c96395f0a926bc13b1c17622aaddda1ecb55d49c8f1bf9777e4d877800a43f8b"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "pin-project-lite"
 version = "0.2.17"
@@ -2500,7 +2640,8 @@ dependencies = [
  "axum-server",
  "base64",
  "chrono",
- "dashmap",
+ "dashmap 6.1.0",
+ "governor 0.6.3",
  "hex",
  "ipnet",
  "jsonwebtoken",
@@ -2520,6 +2661,7 @@ dependencies = [
  "tokio",
  "tower",
  "tower-http",
+ "tower_governor",
  "tracing",
  "tracing-subscriber",
  "ulid",
@@ -2600,6 +2742,12 @@ dependencies = [
  "bstr",
 ]
 
+[[package]]
+name = "portable-atomic"
+version = "1.13.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c33a9471896f1c69cecef8d20cbe2f7accd12527ce60845ff44c153bb2a21b49"
+
 [[package]]
 name = "potential_utf"
 version = "0.1.5"
@@ -2662,6 +2810,21 @@ version = "0.1.29"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e0c5ccf5294c6ccd63a74f1565028353830a9c2f5eb0c682c355c471726a6e3f"
 
+[[package]]
+name = "quanta"
+version = "0.12.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f3ab5a9d756f0d97bdc89019bd2e4ea098cf9cde50ee7564dde6b81ccc8f06c7"
+dependencies = [
+ "crossbeam-utils",
+ "libc",
+ "once_cell",
+ "raw-cpuid",
+ "wasi",
+ "web-sys",
+ "winapi",
+]
+
 [[package]]
 name = "quinn"
 version = "0.11.9"
@@ -2803,6 +2966,15 @@ dependencies = [
  "getrandom 0.3.4",
 ]
 
+[[package]]
+name = "raw-cpuid"
+version = "11.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "498cd0dc59d73224351ee52a95fee0f1a617a2eae0e7d9d720cc622c73a54186"
+dependencies = [
+ "bitflags 2.11.1",
+]
+
 [[package]]
 name = "rcgen"
 version = "0.13.2"
@@ -2999,7 +3171,7 @@ dependencies = [
  "errno",
  "libc",
  "linux-raw-sys",
- "windows-sys 0.60.2",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -3307,7 +3479,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3a766e1110788c36f4fa1c2b71b387a7815aa65f88ce0229841826633d93723e"
 dependencies = [
  "libc",
- "windows-sys 0.60.2",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -3319,6 +3491,15 @@ dependencies = [
  "lock_api",
 ]
 
+[[package]]
+name = "spinning_top"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d96d2d1d716fb500937168cc09353ffdc7a012be8475ac7308e1bdf0e3923300"
+dependencies = [
+ "lock_api",
+]
+
 [[package]]
 name = "spki"
 version = "0.7.3"
@@ -3612,7 +3793,7 @@ dependencies = [
  "getrandom 0.4.2",
  "once_cell",
  "rustix",
- "windows-sys 0.60.2",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -3912,6 +4093,35 @@ version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5d99f8c9a7727884afe522e9bd5edbfc91a3312b36a77b5fb8926e4c31a41801"
 
+[[package]]
+name = "tonic"
+version = "0.14.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ac2a5518c70fa84342385732db33fb3f44bc4cc748936eb5833d2df34d6445ef"
+dependencies = [
+ "async-trait",
+ "axum",
+ "base64",
+ "bytes",
+ "h2",
+ "http",
+ "http-body",
+ "http-body-util",
+ "hyper",
+ "hyper-timeout",
+ "hyper-util",
+ "percent-encoding",
+ "pin-project",
+ "socket2",
+ "sync_wrapper",
+ "tokio",
+ "tokio-stream",
+ "tower",
+ "tower-layer",
+ "tower-service",
+ "tracing",
+]
+
 [[package]]
 name = "totp-rs"
 version = "5.7.1"
@@ -3936,9 +4146,12 @@ checksum = "ebe5ef63511595f1344e2d5cfa636d973292adc0eec1f0ad45fae9f0851ab1d4"
 dependencies = [
  "futures-core",
  "futures-util",
+ "indexmap",
  "pin-project-lite",
+ "slab",
  "sync_wrapper",
  "tokio",
+ "tokio-util",
  "tower-layer",
  "tower-service",
  "tracing",
@@ -3985,6 +4198,23 @@ version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8df9b6e13f2d32c91b9bd719c00d1958837bc7dec474d94952798cc8e69eeec3"
 
+[[package]]
+name = "tower_governor"
+version = "0.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "44de9b94d849d3c46e06a883d72d408c2de6403367b39df2b1c9d9e7b6736fe6"
+dependencies = [
+ "axum",
+ "forwarded-header-value",
+ "governor 0.10.4",
+ "http",
+ "pin-project",
+ "thiserror 2.0.18",
+ "tonic",
+ "tower",
+ "tracing",
+]
+
 [[package]]
 name = "tracing"
 version = "0.1.44"
@@ -4477,7 +4707,7 @@ version = "0.1.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c2a7b1c03c876122aa43f3020e6c3c3ee5c05081c9a00739faf7503aeba10d22"
 dependencies = [
- "windows-sys 0.48.0",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]