internal: Remove temporary sbt-airframe CI/release bootstrap (#4188)

## Why

`sbt-airframe 2026.2.2` and its `airframe-*` dependencies are now
published on Maven Central, so the root build's metabuild resolves the
plugin normally. The temporary `bootstrap-sbt-airframe` composite action
(added to break the first-release deadlock) is no longer needed.

## What

- Delete `.github/actions/bootstrap-sbt-airframe/`.
- Remove its `- uses:` steps from `test.yml` (11),
`sbt-integration.yml`, and the four release workflows.
- `SBT_AIRFRAME_VERSION` stays pinned to the released `2026.2.2`; a
comment now warns against bumping it to the in-development version (that
would reintroduce the release-time metabuild deadlock) — same discipline
as `AIRSPEC_VERSION`.

## Verified

Cleared the locally-published `2026.2.2` artifacts and confirmed the
root build resolves `sbt-airframe 2026.2.2` **from Central** (no local
publish, no bootstrap): `integrationTest/airframeHttpClients` resolves
correctly.

CI on this PR is the real end-to-end check that Central resolution works
without the bootstrap.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: xerial

.github/actions/bootstrap-sbt-airframe/action.yml

@@ -27,8 +27,6 @@ jobs:
         env:
           PGP_SECRET: ${{ secrets.PGP_SECRET }}
         run: echo $PGP_SECRET | base64 --decode | gpg --import --batch --yes
-      # The root build's metabuild needs the (not-yet-released) sbt-airframe plugin to load.
-      - uses: ./.github/actions/bootstrap-sbt-airframe
       - name: Build for Scala.js
         env:
           PGP_PASSPHRASE: ${{ secrets.PGP_PASSPHRASE }}

.github/workflows/release-js.yml

@@ -29,8 +29,6 @@ jobs:
         env:
           PGP_SECRET: ${{ secrets.PGP_SECRET }}
         run: echo $PGP_SECRET | base64 --decode | gpg --import --batch --yes
-      # The root build's metabuild needs the (not-yet-released) sbt-airframe plugin to load.
-      - uses: ./.github/actions/bootstrap-sbt-airframe
       - name: Build for Scala Native
         env:
           PGP_PASSPHRASE: ${{ secrets.PGP_PASSPHRASE }}

.github/workflows/release-native.yml

@@ -28,11 +28,6 @@ jobs:
         env:
           PGP_SECRET: ${{ secrets.PGP_SECRET }}
         run: echo $PGP_SECRET | base64 --decode | gpg --import --batch --yes
-      # Break the release-time circular dependency: the root build's metabuild needs the
-      # sbt-airframe plugin to load, but sbt-airframe is what we're releasing. Publish it locally
-      # FIRST, before AIRFRAME_VERSION is set, so its own deps resolve from the last released
-      # airframe on Maven Central rather than the (not-yet-built) release version.
-      - uses: ./.github/actions/bootstrap-sbt-airframe
       - name: Get Airframe version
         run: echo "AIRFRAME_VERSION=$(./scripts/dynver.sh)" >> $GITHUB_ENV
       - name: Check Airframe version

.github/workflows/release-sbt-plugin.yml

@@ -27,8 +27,6 @@ jobs:
         env:
           PGP_SECRET: ${{ secrets.PGP_SECRET }}
         run: echo $PGP_SECRET | base64 --decode | gpg --import --batch --yes
-      # The root build's metabuild needs the (not-yet-released) sbt-airframe plugin to load.
-      - uses: ./.github/actions/bootstrap-sbt-airframe
       - name: Build bundle
         env:
           PGP_PASSPHRASE: ${{ secrets.PGP_PASSPHRASE }}

.github/workflows/release.yml

@@ -44,8 +44,6 @@ jobs:
         with:
           distribution: 'zulu'
           java-version: '21'
-      # The root build's metabuild needs the (not-yet-released) sbt-airframe plugin to load.
-      - uses: ./.github/actions/bootstrap-sbt-airframe
       - name: Get Airframe version
         run: echo "AIRFRAME_VERSION=$(./scripts/dynver.sh)" >> $GITHUB_ENV
       - name: Check Airframe version

.github/workflows/sbt-integration.yml

@@ -42,7 +42,6 @@ jobs:
     if: needs.changes.outputs.tests == 'true'
     steps:
       - uses: actions/checkout@v6
-      - uses: ./.github/actions/bootstrap-sbt-airframe
       - name: scalafmt in Scala 2.x
         run: ./sbt "++ 2.13; scalafmtCheckAll"
       - name: scalafmt in Scala 3
@@ -64,7 +63,6 @@ jobs:
         with:
           distribution: 'zulu'
           java-version: '21'
-      - uses: ./.github/actions/bootstrap-sbt-airframe
       - name: Scala 2.12 test
         run: ./sbt "++2.12; projectJVM/test"
       - name: Publish Test Report
@@ -86,7 +84,6 @@ jobs:
         with:
           distribution: 'zulu'
           java-version: '21'
-      - uses: ./.github/actions/bootstrap-sbt-airframe
       - name: Scala 2.13 test
         run: ./sbt "++2.13; projectJVM/test"
       - name: Publish Test Report
@@ -108,7 +105,6 @@ jobs:
         with:
           distribution: 'zulu'
           java-version: '21'
-      - uses: ./.github/actions/bootstrap-sbt-airframe
       - name: Scala 3.x test
         # Test only Scala 3 supported projects
         run: ./sbt "++ 3; projectDotty/test; dottyTest/run"
@@ -131,7 +127,6 @@ jobs:
         with:
           distribution: 'zulu'
           java-version: '21'
-      - uses: ./.github/actions/bootstrap-sbt-airframe
       - name: Scala 3.7.x test
         # Test only Scala 3 supported projects
         run: SCALA_VERSION=3.7.1 ./sbt "projectDotty/test; dottyTest/run"
@@ -154,7 +149,6 @@ jobs:
         with:
           distribution: 'zulu'
           java-version: '25'
-      - uses: ./.github/actions/bootstrap-sbt-airframe
       - name: Scala 3 test
         # Test only Scala 3 supported projects
         run: ./sbt "++ 3; projectDotty/test; dottyTest/run"
@@ -186,7 +180,6 @@ jobs:
           cache: 'pnpm'
       - name: Node.js setup
         run: ./scripts/setup-scalajs.sh
-      - uses: ./.github/actions/bootstrap-sbt-airframe
       - name: Integration Test
         run: ./sbt "++ 3; projectIt/test"
       - name: Publish Test Report
@@ -217,7 +210,6 @@ jobs:
           cache: 'pnpm'
       - name: Node.js setup
         run: ./scripts/setup-scalajs.sh
-      - uses: ./.github/actions/bootstrap-sbt-airframe
       - name: Scala.js test
         run: JVM_OPTS=-Xmx4g ./sbt "++ 2.12; projectJS/test"
       - name: Publish Test Report
@@ -248,7 +240,6 @@ jobs:
           cache: 'pnpm'
       - name: Node.js setup
         run: ./scripts/setup-scalajs.sh
-      - uses: ./.github/actions/bootstrap-sbt-airframe
       - name: Scala.js test
         run: JVM_OPTS=-Xmx4g ./sbt "++ 2.13; projectJS/test"
       - name: Publish Test Report
@@ -279,7 +270,6 @@ jobs:
           cache: 'pnpm'
       - name: Node.js setup
         run: ./scripts/setup-scalajs.sh
-      - uses: ./.github/actions/bootstrap-sbt-airframe
       - name: Scala.js test
         run: JVM_OPTS=-Xmx4g ./sbt "++ 3; projectJS/test"
       - name: Publish Test Report
@@ -303,7 +293,6 @@ jobs:
           java-version: '21'
       - name: Install native dependencies
         run: sudo apt-get update && sudo apt-get install -y libcurl4-openssl-dev
-      - uses: ./.github/actions/bootstrap-sbt-airframe
       - name: Scala Native test
         run: JVM_OPTS=-Xmx4g ./sbt "++ 3; projectNative/test"
       - name: Publish Test Report

.github/workflows/test.yml

@@ -40,11 +40,10 @@ addSbtPlugin("org.xerial.sbt"     % "sbt-pack" % "1.0.0")
 // as sbt-antlr4 has no sbt 2.x build
 libraryDependencies += "org.antlr" % "antlr4" % "4.13.2"
 
-// For integration testing.
-// Defaults to the next sbt-airframe release. Until that is published to Maven Central,
-// build sbt-airframe locally and point this at the snapshot:
-//   (cd sbt-airframe && ../sbt publishLocal)
-//   export SBT_AIRFRAME_VERSION=$(./scripts/dynver.sh)
+// For integration testing (the integrationTest project uses AirframeHttpPlugin).
+// Keep this pinned to a RELEASED sbt-airframe on Maven Central (like AIRSPEC_VERSION) — do NOT
+// bump it to the in-development version, or the metabuild can't load while that version is being
+// built (a release-time deadlock). Building sbt-airframe from this repo's source is not required.
 val SBT_AIRFRAME_VERSION = sys.env.getOrElse("SBT_AIRFRAME_VERSION", "2026.2.2")
 addSbtPlugin("org.wvlet.airframe" % "sbt-airframe" % SBT_AIRFRAME_VERSION)