fix(ci): check-try-runtime add warm-cache env + increase timeout to 180m

Job was timing out at 120m because it had no CARGO_HOME or shared
CARGO_TARGET_DIR — every run was a cold registry download + full
cold compile even when test-base jobs had already built the same
crates. Add /root/.cargo pre-baked image registry and share the
same /cache/cargo-target/${CACHE_KEY}/test-release directory used
by .test-base. With warm cache this completes in under 30m.

Increase timeout 120m → 180m as belt-and-suspenders for the case
where this job runs before any .test-base job has warmed the cache.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.gitlab-ci.yml

@@ -268,7 +268,13 @@ check-try-runtime:
   needs: [clippy]
   variables:
     SKIP_WASM_BUILD: "1"
-  timeout: 120m
+    CARGO_HOME: /root/.cargo
+  before_script:
+    - export CACHE_KEY="$(cat Cargo.lock rust-toolchain.toml | md5sum | cut -c1-12)"
+    - export CARGO_TARGET_DIR="/cache/cargo-target/${CACHE_KEY}/test-release"
+    - mkdir -p "$CARGO_TARGET_DIR"
+    - echo "CARGO_TARGET_DIR=$CARGO_TARGET_DIR"
+  timeout: 180m
   script:
     - git config --global --add safe.directory '*'
     # try-runtime,experimental is a superset — covers the separate try-runtime and