ci: add GitHub Actions pipeline (tests, vet) across all workspace modules (#10)

Add .github/workflows/ci.yaml running on pull_request and push to main.
The workflow installs the mise-pinned toolchain (Go 1.26.3) and runs the
same mise tasks used locally — `mise run vet` (new task fanning out over
every go.work module) and `mise run test` with GOFLAGS=-race — so CI and
local dev cannot drift. Actions are pinned by commit SHA. Add a CI status
badge to README.md.

Closes #5

---
_Generated with [`mux`](https://github.com/coder/mux) • Model: `anthropic:claude-fable-5` • Thinking: `xhigh`_

Author: ThomasK33

.github/workflows/ci.yaml

@@ -0,0 +1,41 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+
+permissions:
+  contents: read
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    timeout-minutes: 30
+    steps:
+      - name: Checkout
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+
+      - name: Install mise-pinned toolchain
+        uses: jdx/mise-action@c2a87611a18de5b3828c5652fe268e992400cb5c # v4.3.0
+
+      - name: Cache Go modules
+        uses: actions/cache@55cc8345863c7cc4c66a329aec7e433d2d1c52a9 # v6.1.0
+        with:
+          path: |
+            ~/go/pkg/mod
+            ~/.cache/go-build
+          key: go-${{ runner.os }}-${{ hashFiles('**/go.sum', 'go.work.sum') }}
+          restore-keys: go-${{ runner.os }}-
+
+      - name: Vet
+        run: mise run vet
+
+      - name: Test
+        run: mise run test
+        env:
+          GOFLAGS: -race

README.md

@@ -1,5 +1,7 @@
 # Chat SDK Go
 
+[![CI](https://github.com/coder/chat/actions/workflows/ci.yaml/badge.svg?branch=main)](https://github.com/coder/chat/actions/workflows/ci.yaml)
+
 Chat SDK Go is a Go-native semantic subset of Vercel Chat SDK's
 conversation runtime: adapters, normalized events, threads, subscriptions,
 state-backed dedupe, and thread-scoped replies.

go.work.sum

@@ -32,6 +32,7 @@ golang.org/x/net v0.49.0/go.mod h1:/ysNB2EvaqvesRkuLAyjI1ycPZlQHM3q01F02UY/MV8=
 golang.org/x/net v0.53.0/go.mod h1:JvMuJH7rrdiCfbeHoo3fCQU24Lf5JJwT9W3sJFulfgs=
 golang.org/x/sync v0.13.0/go.mod h1:1dzgHSNfp02xaA81J2MS99Qcpr2w7fw1gpm99rleRqA=
 golang.org/x/sync v0.17.0/go.mod h1:9KTHXmSnoGruLpwFjVSX0lNNA75CykiMECbovNTZqGI=
+golang.org/x/sync v0.20.0 h1:e0PTpb7pjO8GAtTs2dQ6jYa5BWYlMuX047Dco/pItO4=
 golang.org/x/sync v0.20.0/go.mod h1:9xrNwdLfx4jkKbNva9FpL6vEN7evnE43NNNJQ2LF3+0=
 golang.org/x/sys v0.26.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/sys v0.40.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
@@ -41,6 +42,7 @@ golang.org/x/telemetry v0.0.0-20260409153401-be6f6cb8b1fa/go.mod h1:kHjTxDEnAu6/
 golang.org/x/term v0.43.0/go.mod h1:lrhlHNdQJHO+1qVYiHfFKVuVioJIheAc3fBSMFYEIsk=
 golang.org/x/text v0.24.0/go.mod h1:L8rBsPeo2pSS+xqN0d5u2ikmjtmoJbDBT1b7nHvFCdU=
 golang.org/x/text v0.29.0/go.mod h1:7MhJOA9CD2qZyOKYazxdYMF85OwPdEr9jTtBpO7ydH4=
+golang.org/x/text v0.37.0 h1:Cqjiwd9eSg8e0QAkyCaQTNHFIIzWtidPahFWR83rTrc=
 golang.org/x/text v0.37.0/go.mod h1:a5sjxXGs9hsn/AJVwuElvCAo9v8QYLzvavO5z2PiM38=
 golang.org/x/time v0.11.0/go.mod h1:CDIdPxbZBQxdj6cxyCIdrNogrJKMJ7pr37NYpMcMDSg=
 golang.org/x/tools v0.26.0/go.mod h1:TPVVj70c7JJ3WCazhD8OdXcZg/og+b9+tH/KxylGwH0=

mise.toml

@@ -43,6 +43,18 @@ run = "cd state/redis && go test ./..."
 description = "Run tests for the root Go module"
 run = "go test ./..."
 
+[tasks.vet]
+description = "Run go vet for every Go module in the workspace"
+run = [
+  "go vet ./...",
+  "cd state/nats && go vet ./...",
+  "cd state/postgres && go vet ./...",
+  "cd state/redis && go vet ./...",
+  "cd examples/slack-nats-state && go vet ./...",
+  "cd examples/slack-redis-state && go vet ./...",
+  "cd examples/slack-postgres-state && go vet ./...",
+]
+
 [tasks."test:examples"]
 description = "Run example module tests"
 run = [