Unify @github/copilot version tracking and rename sync workflow

Option C: Make reference-impl sync the single entry point for all
@github/copilot version changes. During sync, both pom.xml and
scripts/codegen/package.json are updated from the reference
implementation's nodejs/package.json.

Changes:
- Add sync-codegen-version.sh to update scripts/codegen/package.json
- Update merge-reference-impl-finish.sh to call the new script
- Remove Dependabot npm entry for /scripts/codegen (no longer needed)
- Rename weekly-reference-impl-sync.{yml,md,lock.yml} to
  reference-impl-sync.{yml,md,lock.yml}
- Change schedule from weekly (Monday) to daily
- Remove all 'weekly'/'Weekly' timing references from file contents
- Rename POM property to remove 'weekly' from its name
- Recompile agentic workflow via gh aw compile

.github/actions/setup-copilot/action.yml

@@ -21,7 +21,7 @@ runs:
       # implementation pinned in .lastmerge by
       # .github/scripts/reference-impl-sync/sync-cli-version-from-reference-impl.sh.
       run: |
-        PROP="readonly-copilot-sdk-ref-impl-version-from-lastmerge-file-updated-by-weekly-reference-impl-sync"
+        PROP="readonly-copilot-sdk-ref-impl-version-from-lastmerge-file-updated-by-reference-impl-sync"
         VERSION=$(sed -n "s|.*<${PROP}>\(.*\)</${PROP}>.*|\1|p" pom.xml | head -n 1 | tr -d '[:space:]')
         if [[ -z "$VERSION" || "$VERSION" == "PRIMER_TO_REPLACE" ]]; then
           echo "::error::Could not read pinned @github/copilot version from pom.xml property <${PROP}>" >&2

.github/dependabot.yml

@@ -1,13 +1,5 @@
 version: 2
 updates:
-  - package-ecosystem: "npm"
-    directory: "/scripts/codegen"
-    schedule:
-      interval: "daily"
-    open-pull-requests-limit: 1
-    allow:
-      - dependency-name: "@github/copilot"
-
   - package-ecosystem: "github-actions"
     directory: "/"
     schedule:

.github/prompts/coding-agent-merge-reference-impl-instructions.md

@@ -1,5 +1,5 @@
-<!-- Custom instructions for the Copilot coding agent when triggered by the weekly reference implementation sync workflow. -->
-<!-- This file is read by .github/workflows/weekly-reference-impl-sync.yml and passed as custom_instructions. -->
+<!-- Custom instructions for the Copilot coding agent when triggered by the reference implementation sync workflow. -->
+<!-- This file is read by .github/workflows/reference-impl-sync.yml and passed as custom_instructions. -->
 
 Follow the agentic-merge-reference-impl prompt at .github/prompts/agentic-merge-reference-impl.prompt.md
 to port reference implementation changes to the Java SDK.

.github/scripts/reference-impl-sync/merge-reference-impl-finish.sh

@@ -7,8 +7,10 @@
 #   2. Updates .lastmerge to reference implementation HEAD
 #   3. Syncs the @github/copilot version property in pom.xml from the
 #      cloned reference implementation's nodejs/package.json
-#   4. Commits the .lastmerge + pom.xml updates
-#   5. Pushes the branch to origin
+#   4. Syncs scripts/codegen/package.json to the same @github/copilot
+#      version so the code generator uses matching schemas
+#   5. Commits the .lastmerge + pom.xml + codegen package updates
+#   6. Pushes the branch to origin
 #
 # Usage:  ./.github/scripts/reference-impl-sync/merge-reference-impl-finish.sh
 #         ./.github/scripts/reference-impl-sync/merge-reference-impl-finish.sh --skip-tests
@@ -56,7 +58,15 @@ echo "$NEW_COMMIT" > "$ROOT_DIR/.lastmerge"
 echo "▸ Syncing @github/copilot version in pom.xml from reference implementation…"
 "$ROOT_DIR/.github/scripts/reference-impl-sync/sync-cli-version-from-reference-impl.sh" "$REFERENCE_IMPL_DIR"
 
-git add .lastmerge pom.xml
+# ── 2c. Sync scripts/codegen @github/copilot version ─────────
+# Keeps scripts/codegen/package.json in lockstep so the code generator
+# uses schemas from the same CLI version that the tests run against.
+# This eliminates the gap where Dependabot could race ahead of the
+# reference implementation sync.
+echo "▸ Syncing @github/copilot version in scripts/codegen/package.json…"
+"$ROOT_DIR/.github/scripts/reference-impl-sync/sync-codegen-version.sh" "$REFERENCE_IMPL_DIR"
+
+git add .lastmerge pom.xml scripts/codegen/package.json scripts/codegen/package-lock.json
 git commit -m "Update .lastmerge to $NEW_COMMIT and sync pom.xml CLI version"
 
 # ── 3. Push branch ───────────────────────────────────────────

.github/scripts/reference-impl-sync/sync-cli-version-from-reference-impl.sh

@@ -6,7 +6,7 @@
 # reference implementation's nodejs/package.json, and updates the
 # corresponding property in pom.xml:
 #
-#   <readonly-copilot-sdk-ref-impl-version-from-lastmerge-file-updated-by-weekly-reference-impl-sync>
+#   <readonly-copilot-sdk-ref-impl-version-from-lastmerge-file-updated-by-reference-impl-sync>
 #
 # This keeps the canonical Copilot CLI version (declared in pom.xml)
 # in sync with whatever the reference implementation pinned in
@@ -65,7 +65,7 @@ if [[ -z "$CLI_VERSION" ]]; then
 fi
 
 POM="$ROOT_DIR/pom.xml"
-PROP="readonly-copilot-sdk-ref-impl-version-from-lastmerge-file-updated-by-weekly-reference-impl-sync"
+PROP="readonly-copilot-sdk-ref-impl-version-from-lastmerge-file-updated-by-reference-impl-sync"
 
 if ! grep -q "<${PROP}>" "$POM"; then
     echo "❌ Property <${PROP}> not found in $POM" >&2

.github/scripts/reference-impl-sync/sync-codegen-version.sh

@@ -0,0 +1,69 @@
+#!/usr/bin/env bash
+# ──────────────────────────────────────────────────────────────
+# sync-codegen-version.sh
+#
+# Updates the @github/copilot dependency in scripts/codegen/package.json
+# to match the version used by the reference implementation. This keeps
+# the code generator schemas in lockstep with the CLI version used for
+# testing, eliminating the gap where Dependabot could race ahead.
+#
+# Usage:
+#   ./sync-codegen-version.sh <reference-impl-dir>
+#
+# Or, when invoked from merge-reference-impl-finish.sh, the directory
+# is passed as $1.
+# ──────────────────────────────────────────────────────────────
+set -euo pipefail
+
+# Locate the repo root by walking up from this script until we find a pom.xml.
+find_repo_root() {
+    local dir
+    dir="$(cd "$(dirname "$0")" && pwd)"
+    while [[ "$dir" != "/" ]]; do
+        if [[ -f "$dir/pom.xml" ]]; then
+            echo "$dir"
+            return 0
+        fi
+        dir="$(dirname "$dir")"
+    done
+    echo "❌ Could not locate repo root (no pom.xml found above $(dirname "$0"))" >&2
+    return 1
+}
+ROOT_DIR="$(find_repo_root)"
+
+REFERENCE_IMPL_DIR="${1:-${REFERENCE_IMPL_DIR:-}}"
+if [[ -z "$REFERENCE_IMPL_DIR" ]]; then
+    echo "❌ Usage: $0 <reference-impl-dir>" >&2
+    echo "   or set REFERENCE_IMPL_DIR in the environment." >&2
+    exit 1
+fi
+
+PKG_JSON="$REFERENCE_IMPL_DIR/nodejs/package.json"
+if [[ ! -f "$PKG_JSON" ]]; then
+    echo "❌ Cannot find $PKG_JSON" >&2
+    exit 1
+fi
+
+# Extract the @github/copilot version from the reference implementation.
+CLI_VERSION=$(node -e \
+    "const fs=require('fs');const p=JSON.parse(fs.readFileSync(process.argv[1],'utf8'));const v=(p.dependencies&&p.dependencies['@github/copilot'])||(p.devDependencies&&p.devDependencies['@github/copilot']);process.stdout.write(v||'');" \
+    "$PKG_JSON")
+
+if [[ -z "$CLI_VERSION" ]]; then
+    echo "❌ Could not extract @github/copilot version from $PKG_JSON" >&2
+    exit 1
+fi
+
+CODEGEN_DIR="$ROOT_DIR/scripts/codegen"
+CODEGEN_PKG="$CODEGEN_DIR/package.json"
+
+if [[ ! -f "$CODEGEN_PKG" ]]; then
+    echo "❌ Cannot find $CODEGEN_PKG" >&2
+    exit 1
+fi
+
+# Update scripts/codegen/package.json with the new version and regenerate the lock file.
+echo "▸ Updating scripts/codegen/package.json: @github/copilot → ${CLI_VERSION}"
+cd "$CODEGEN_DIR"
+npm install "@github/copilot@${CLI_VERSION}" --save-exact
+echo "▸ Updated scripts/codegen to @github/copilot@${CLI_VERSION}"