chore(config): lint tests + examples in pre-push clippy (#967)

The pre-push clippy invocation ran without --all-targets, so it only checked
lib + bins — test and example targets were never clippy-linted, which is how
the cfg(test)/test-target debt cleared in the previous commit accumulated
unflagged. Add --all-targets now that the debt is clean.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.config/hooks/pre-push

@@ -87,10 +87,12 @@ elif command -v cargo >/dev/null 2>&1 && [ -d "$REPO_ROOT/server" ]; then
         echo "pre-push: fmt — OK"
     fi
 
-    # clippy needs a build — skip if target/ doesn't exist (cold worktree)
+    # clippy needs a build — skip if target/ doesn't exist (cold worktree).
+    # --all-targets lints tests + examples too (#967 closed the gap where test
+    # code accumulated clippy debt unchecked).
     if [ -d "$REPO_ROOT/server/target" ]; then
         echo "pre-push: checking Rust (clippy)..."
-        if ! (cd "$REPO_ROOT/server" && cargo clippy -- -D warnings 2>&1); then
+        if ! (cd "$REPO_ROOT/server" && cargo clippy --all-targets -- -D warnings 2>&1); then
             ERRORS=$((ERRORS + 1))
         else
             echo "pre-push: clippy — OK"