feat(git-tools): consume .mosaic/repo.json declarations in compat mode (T51 WP5b) (#1416)

Co-authored-by: code-be-02 <[email protected]>

packages/mosaic/framework/tools/git/ci-queue-wait.sh

@@ -503,6 +503,28 @@ if [[ -z "$BRANCH" ]]; then
     fi
 fi
 
+# T51 WP5b (spec 4.1, review ruling C4/F8): the declaration adds ROUTE CONTEXT only.
+# Branch-selection semantics are UNCHANGED — the guard keeps inspecting the
+# exact head above. No declaration dependency gates the wait (4.3/DR2 R9:
+# blocking here adds a blocker with no safety gain); absence is silent.
+# shellcheck source=packages/mosaic/framework/tools/git/ci-queue-wait.sh
+if git rev-parse --show-toplevel >/dev/null 2>&1 \
+   && [ -f "$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)/repo-decl.sh" ]; then
+    source "$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)/repo-decl.sh"
+    repo_decl_load
+    if [[ "$DECL_STATE" == invalid ]]; then
+        repo_decl_report_invalid
+    elif [[ "$DECL_STATE" == valid && "$DECL_SCHEMA" == 2 ]]; then
+        route="feature"
+        if [[ "$BRANCH" == "$DECL_TRUNK" ]]; then
+            route="trunk (integration head)"
+        elif [[ "$BRANCH" == "$DECL_RELEASE" ]]; then
+            route="release branch"
+        fi
+        echo "repo-decl: route context flow=$DECL_FLOW trunk=$DECL_TRUNK release=$DECL_RELEASE; guarded head '$BRANCH' is a $route head (spec 4.1)" >&2
+    fi
+fi
+
 if [[ "$PLATFORM" == "github" ]]; then
     if ! command -v gh >/dev/null 2>&1; then
         record_cannot_assert "github-cli-unavailable"