experiment: E1 lld + test-profile tweaks (apt without sudo)

Pool runner is root; golden /etc/sudoers is mis-owned so sudo fails.
lld via apt, RUSTFLAGS=-C link-arg=-fuse-ld=lld, profile.test debug=0,
dev build-override opt-level=3 for proc macros.

Author: Bnjoroge1

.github/workflows/ci.yml

@@ -57,6 +57,7 @@ jobs:
       # concurrency so the dogfood VM survives preloop-runner's suite.
       PROPTEST_CASES: "8"
       RUST_TEST_THREADS: "2"
+      RUSTFLAGS: "-C link-arg=-fuse-ld=lld"
     steps:
       - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
         with:
@@ -81,6 +82,11 @@ jobs:
       # inline run steps work against preloop
       - uses: Swatinem/rust-cache@49a0bdc70d2e1b713ca9e2869b211fcce03d3c1c
 
+      # Runner executes as root in the pool VM; sudo's audit plugin fails on
+      # the mis-owned /etc/sudoers in the golden, so call apt directly.
+      - name: Install lld linker
+        run: apt-get update && apt-get install -y --no-install-recommends lld
+
       - run: cargo fmt --all --check
       - run: |
           # Run clippy on warning-free crates with strict -D warnings
@@ -89,7 +95,7 @@ jobs:
           cargo clippy --locked -p preloop-runner -p preloop-runner-server -p preloop-runner-client -p preloop-dap --all-targets
       - run: cargo test --locked --workspace
         env:
-          RUSTFLAGS: "-A warnings"
+          RUSTFLAGS: "-A warnings -C link-arg=-fuse-ld=lld"
 
   # Bounded property-test profile
   property-tests-fast:

Cargo.toml

@@ -102,5 +102,15 @@ lto = "thin"
 codegen-units = 1
 strip = true
 
+[profile.dev.build-override]
+# Proc macros and build scripts are executed, not shipped; optimize them
+# so the compiler spends less time inside them during dev/test builds.
+opt-level = 3
+
+[profile.test]
+# CI test binaries: skip DWARF emission (smaller artifacts, faster codegen
+# and link). Panic backtraces lose line numbers in tests — acceptable.
+debug = 0
+
 [profile.dist]
 inherits = "release"