Clear CodeQL and Sonar security findings from the broker PR

The gateway URL's trailing slashes were stripped with /\/+$/, which CodeQL
flags as polynomial on a URL of many slashes; a plain loop replaces it.
CI now pins setup-bun to a commit and installs with --ignore-scripts, and
run-all.sh uses [[ ]].

Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_012AuVk4nEvBXaTjs4G6wdW4

.github/workflows/ci.yml

@@ -14,9 +14,9 @@ jobs:
     timeout-minutes: 15
     steps:
       - uses: actions/checkout@v4
-      - uses: oven-sh/setup-bun@v2
+      - uses: oven-sh/setup-bun@0c5077e51419868618aeaa5fe8019c62421857d6 # v2.2.0
         with:
           bun-version: 1.4.2
-      - run: bun install --frozen-lockfile
+      - run: bun install --frozen-lockfile --ignore-scripts
       - run: make check
       - run: make accept

scripts/accept/run-all.sh

@@ -7,7 +7,7 @@ set -euo pipefail
 cd "$(dirname "$0")/../.."
 
 mapfile -t scripts < <(find scripts/accept -maxdepth 1 -name 'wave-*.sh' -print | sort -V)
-if [ "${#scripts[@]}" -eq 0 ]; then
+if [[ "${#scripts[@]}" -eq 0 ]]; then
   echo "FAIL: no scripts/accept/wave-*.sh found" >&2
   exit 1
 fi

src/lazy-broker/backends.ts

@@ -82,12 +82,19 @@ export function remoteToolName(server: string, catalogName: string): string {
   return catalogName.slice(prefix.length);
 }
 
+/** Drops trailing slashes without a regex, so a hostile URL stays linear. */
+function stripTrailingSlashes(url: string): string {
+  let end = url.length;
+  while (end > 0 && url[end - 1] === "/") end--;
+  return url.slice(0, end);
+}
+
 /** Per-target MCP endpoint on the gateway: `${gateway}/mcp/<target>`. */
 export function targetUrl(gatewayUrl: string, server: string): string {
-  return `${gatewayUrl.replace(/\/+$/, "")}/mcp/${endpointFor(server).target}`;
+  return `${stripTrailingSlashes(gatewayUrl)}/mcp/${endpointFor(server).target}`;
 }
 
 /** Multiplexed MCP endpoint on the gateway (all targets, prefixed names). */
 export function multiplexedUrl(gatewayUrl: string): string {
-  return `${gatewayUrl.replace(/\/+$/, "")}/mcp`;
+  return `${stripTrailingSlashes(gatewayUrl)}/mcp`;
 }