ci: sync upstream 0.9.87 and enforce clean server sources

.cargo/config.toml

@@ -28,6 +28,13 @@
 [env]
 JEMALLOC_SYS_WITH_MALLOC_CONF = "background_thread:true,dirty_decay_ms:1000,muzzy_decay_ms:1000,thp:never"
 
+# ── MSRV-aware updates (issue #48) ──────────────────────────────────────────
+# Keep `cargo update` on dependency versions that build with the declared
+# rust-version (1.75). Cargo 1.84+ reads this; older Cargo warns about an
+# unused key and goes on.
+[resolver]
+incompatible-rust-versions = "fallback"
+
 # ── Optional CPU optimization (uncomment ONE that matches YOUR build host) ───
 # Commented out so the project builds portably everywhere. Enabling a specific
 # target-cpu produces a binary tuned to that microarchitecture — only run such a

.github/workflows/ci.yml

@@ -16,8 +16,28 @@ permissions:
 env:
   CARGO_TERM_COLOR: always
   RUST_BACKTRACE: 1
+  UPSTREAM_COMMIT: 3742f9e4bc64e36faf4b8ed4cb355be3744ff96c
 
 jobs:
+  upstream-clean:
+    name: Upstream-owned paths are unchanged
+    runs-on: ubuntu-24.04
+    steps:
+      - name: Checkout
+        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+
+      - name: Fetch reviewed upstream commit
+        run: >-
+          git fetch --no-tags --depth=1
+          https://github.com/andrey23127/ed2k-server.git
+          "${UPSTREAM_COMMIT}"
+
+      - name: Reject fork source divergence
+        run: |
+          git diff --exit-code --ignore-space-at-eol "${UPSTREAM_COMMIT}" -- \
+            .cargo CHANGELOG.md CPU-TUNING.md Cargo.lock Cargo.toml LICENSE \
+            README.md UPDATE-SERVICE.md assets config contrib examples src tests
+
   msrv:
     name: Rust 1.75 locked test
     runs-on: ubuntu-24.04

AGENTS.md

@@ -17,9 +17,11 @@ Everything below is this repo's local deltas only:
   under `EMULEBB_WORKSPACE_OUTPUT_ROOT`.
 - The fork is the sole approved local server for deterministic harness and
   parity runs. The retired Go server is archived and must not be reintroduced.
-- Follow upstream closely. Limit local server changes to generic, upstreamable
-  testing and observability improvements; keep provider-specific configuration,
-  compatibility translation, fixtures, and orchestration in the harness.
+- Keep every upstream-owned runtime, protocol, configuration, dependency, test,
+  and documentation path identical to the reviewed upstream commit pinned by
+  CI. Do not carry local server behavior, observability, or compatibility
+  changes. Contribute generic changes upstream first; keep probes, fixtures,
+  diagnostics adapters, and orchestration in the harness.
 - The fork is not an eMuleBB product or production service. Do not wire it into
   release or production campaigns without an explicit follow-up decision.
 - Upstream updates are reviewed merges from the `upstream` remote. Do not add