refactor(core): source pricing + context limits from tokenlens registry

.github/workflows/registry-check.yml

@@ -0,0 +1,62 @@
+name: Registry check
+
+on:
+  schedule:
+    - cron: '0 12 * * 1'
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  issues: write
+
+jobs:
+  check:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+          cache: 'npm'
+          registry-url: 'https://registry.npmjs.org/'
+      - run: npm ci
+      - run: npm run build -w @tokenometer/core
+      - id: check
+        run: |
+          set +e
+          OUTPUT=$(npm run --silent check:overrides -w @tokenometer/core 2>&1)
+          STATUS=$?
+          {
+            echo 'output<<EOF'
+            echo "$OUTPUT"
+            echo 'EOF'
+          } >> "$GITHUB_OUTPUT"
+          echo "status=$STATUS" >> "$GITHUB_OUTPUT"
+          echo "$OUTPUT"
+          exit 0
+      - name: Open or update tracking issue on findings
+        if: steps.check.outputs.status != '0'
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          BODY: |
+            The weekly tokenlens registry check found findings.
+
+            ```
+            ${{ steps.check.outputs.output }}
+            ```
+
+            Resolve by either:
+            - Deleting the listed `LOCAL_OVERRIDES` entries in `packages/core/src/rates.ts`, or
+            - Reviewing upstream pricing/context drift and refreshing the snapshot via
+              `npm run snapshot:registry -w @tokenometer/core`.
+        run: |
+          TITLE='[registry-check] tokenlens upstream changes detected'
+          EXISTING=$(gh issue list --search "$TITLE in:title is:open" --json number --jq '.[0].number')
+          if [ -n "$EXISTING" ]; then
+            gh issue comment "$EXISTING" --body "$BODY"
+          else
+            gh issue create --title "$TITLE" --body "$BODY" --label registry-check
+          fi
+      - name: Fail job if findings present
+        if: steps.check.outputs.status != '0'
+        run: exit 1