Community files and CI, now that the repository is public

It had none: no security policy, no contributing guide, no code of conduct,
no sponsor link, and no CI. A public repository with an administrative
interface in it should at least say where to send a vulnerability, so that
part names what is worth reporting here specifically -- a session acting
beyond its permissions, one tenant's data reaching another, a token landing
somewhere that outlives the session -- and where a report goes if it turns
out to belong to the server or to upstream.

CI is what a contributor can run: typecheck, lint, test, build. Nothing in
it needs a live server, so a red run means the code, not the runner.

.github/FUNDING.yml

@@ -0,0 +1,4 @@
+# Funding platforms shown behind the repository's Sponsor button.
+# https://docs.github.com/repositories/managing-your-repositorys-settings-and-features/customizing-your-repository/displaying-a-sponsor-button-in-your-repository
+
+github: jcoffey-dev

.github/dependabot.yml

@@ -0,0 +1,31 @@
+version: 2
+updates:
+  # One npm entry at the root, where the single lockfile is.
+  #
+  # Minor and patch arrive as one pull request a week. Majors are left out of
+  # the group on purpose: they are migrations rather than bumps, and each one
+  # deserves its own pull request and its own CI run.
+  - package-ecosystem: npm
+    directory: "/"
+    schedule:
+      interval: weekly
+      day: tuesday
+      time: "09:00"
+      timezone: Etc/UTC
+    open-pull-requests-limit: 5
+    groups:
+      minor-and-patch:
+        update-types:
+          - minor
+          - patch
+  - package-ecosystem: github-actions
+    directory: "/"
+    schedule:
+      interval: weekly
+      day: tuesday
+      time: "09:00"
+      timezone: Etc/UTC
+    groups:
+      actions:
+        patterns:
+          - "*"

.github/workflows/ci.yml

@@ -0,0 +1,31 @@
+name: CI
+on:
+  push:
+    branches: [main]
+  pull_request:
+  workflow_dispatch:
+
+concurrency:
+  group: ci-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      # Pinned to full commit SHAs, with the release in the trailing comment.
+      # A tag is a mutable pointer, so trusting `@v7` is trusting every future
+      # version of that action. Dependabot updates both halves together on its
+      # weekly run -- do not "simplify" a pin back to a tag.
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+      - uses: actions/setup-node@820762786026740c76f36085b0efc47a31fe5020 # v7.0.0
+        with:
+          node-version: 22
+          cache: npm
+      # --ignore-scripts: a postinstall script in any transitive dependency
+      # would otherwise run with the runner's token in its environment.
+      - run: npm ci --ignore-scripts
+      - run: npm run typecheck
+      - run: npm run lint
+      - run: npm test
+      - run: npm run build