chore(ci): upgrade actions to v6 for Node 24 compatibility

GitHub will force Node.js 24 for all actions starting June 16, 2026.

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

Author: XXPermanentXX

.github/workflows/ci.yml

@@ -14,11 +14,11 @@ jobs:
     name: lint + typecheck + test
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
-      - uses: pnpm/action-setup@v4
+      - uses: pnpm/action-setup@v6
 
-      - uses: actions/setup-node@v4
+      - uses: actions/setup-node@v6
         with:
           node-version: "22"
           cache: pnpm

.github/workflows/publish.yml

@@ -29,11 +29,11 @@ jobs:
       contents: write # push lightweight tag to origin
       id-token: write # OIDC for npm Trusted Publishing + provenance
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
-      - uses: pnpm/action-setup@v4
+      - uses: pnpm/action-setup@v6
 
-      - uses: actions/setup-node@v4
+      - uses: actions/setup-node@v6
         with:
           node-version: "24"
           cache: pnpm
@@ -61,11 +61,11 @@ jobs:
       contents: read # no tag, no Release; just publish
       id-token: write # OIDC for npm Trusted Publishing + provenance
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
-      - uses: pnpm/action-setup@v4
+      - uses: pnpm/action-setup@v6
 
-      - uses: actions/setup-node@v4
+      - uses: actions/setup-node@v6
         with:
           node-version: "24"
           cache: pnpm