p0 line landing: coord board/roll + wrapper usage contract + dispatch layer (successor to #1467) (#1468)

Co-authored-by: orch-01 <[email protected]>

packages/mosaic/framework/tools/git/milestone-create.sh

@@ -3,6 +3,7 @@
 # Usage: milestone-create.sh -t "Title" [-d "Description"] [--due "YYYY-MM-DD"]
 
 set -e
+set -o pipefail
 
 SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 source "$SCRIPT_DIR/detect-platform.sh"
@@ -37,21 +38,31 @@ Examples:
     $(basename "$0") -t "0.0.1" -d "Pre-MVP Foundation Sprint"
     $(basename "$0") -t "0.1.0" -d "MVP Release" --due "2025-03-01"
 EOF
-    exit "${1:-1}"
+    exit "${1:-2}"
 }
 
 # Parse arguments
+# Usage-error contract (R4, 2026-08-28): usage errors print to STDERR and exit 2,
+# distinct from provider, credential, and verification failures (exit 1).
+usage_error() {
+    echo "Error: $*" >&2
+    usage >&2
+}
+
 while [[ $# -gt 0 ]]; do
     case $1 in
         -t|--title)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             TITLE="$2"
             shift 2
             ;;
         -d|--desc)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             DESCRIPTION="$2"
             shift 2
             ;;
         --due)
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             DUE_DATE="$2"
             shift 2
             ;;
@@ -74,14 +85,18 @@ PLATFORM=$(detect_platform)
 if [[ "$LIST_ONLY" == true ]]; then
     case "$PLATFORM" in
         github)
-            gh api repos/:owner/:repo/milestones --jq '.[] | "\(.number)\t\(.title)\t\(.state)\t\(.open_issues)/\(.closed_issues) issues"'
+            prov_rc=0
+            gh api repos/:owner/:repo/milestones --jq '.[] | "\(.number)\t\(.title)\t\(.state)\t\(.open_issues)/\(.closed_issues) issues"' || prov_rc=$?
+            [[ "$prov_rc" -eq 0 ]] || { echo "Error: provider command failed (exit ${prov_rc}; provider failure, not a usage error)" >&2; exit 1; }
             ;;
         gitea)
             REPO_ARGS=$(get_gitea_repo_args) || {
                 echo "Error: Could not resolve Gitea repo/login for remote host" >&2
                 exit 1
             }
-            tea milestones list $REPO_ARGS
+            prov_rc=0
+            tea milestones list $REPO_ARGS || prov_rc=$?
+            [[ "$prov_rc" -eq 0 ]] || { echo "Error: provider command failed (exit ${prov_rc}; provider failure, not a usage error)" >&2; exit 1; }
             ;;
         *)
             echo "Error: Could not detect git platform" >&2
@@ -92,8 +107,7 @@ if [[ "$LIST_ONLY" == true ]]; then
 fi
 
 if [[ -z "$TITLE" ]]; then
-    echo "Error: Title is required (-t) for creating milestones" >&2
-    usage
+    usage_error "Title is required (-t) for creating milestones"
 fi
 
 case "$PLATFORM" in
@@ -109,7 +123,9 @@ case "$PLATFORM" in
              + (if $d != "" then {"description": $d} else {} end)
              + (if $due != "" then {"due_on": ($due + "T00:00:00Z")} else {} end)')
 
-        gh api repos/:owner/:repo/milestones --method POST --input - <<< "$JSON_PAYLOAD"
+        prov_rc=0
+        gh api repos/:owner/:repo/milestones --method POST --input - <<< "$JSON_PAYLOAD" || prov_rc=$?
+        [[ "$prov_rc" -eq 0 ]] || { echo "Error: provider command failed (exit ${prov_rc}; provider failure, not a usage error)" >&2; exit 1; }
         echo "Milestone '$TITLE' created successfully"
         ;;
     gitea)
@@ -120,7 +136,9 @@ case "$PLATFORM" in
         CMD=(tea milestones create --title "$TITLE")
         [[ -n "$DESCRIPTION" ]] && CMD+=(--description "$DESCRIPTION")
         [[ -n "$DUE_DATE" ]] && CMD+=(--deadline "$DUE_DATE")
-        "${CMD[@]}" $REPO_ARGS
+        prov_rc=0
+        "${CMD[@]}" $REPO_ARGS || prov_rc=$?
+        [[ "$prov_rc" -eq 0 ]] || { echo "Error: provider command failed (exit ${prov_rc}; provider failure, not a usage error)" >&2; exit 1; }
         echo "Milestone '$TITLE' created successfully"
         ;;
     *)