develop is the trunk; main holds released code and moves by fast-forward at a release

CI runs on merges to develop (and on fork pull requests); the release workflow builds the draft
from a push to main. AGENTS.md, CONTRIBUTING.md and docs/releasing.md follow.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm

.github/workflows/ci.yml

@@ -1,7 +1,8 @@
 name: CI
 
-# CI runs once per merge, on main (AGENTS.md, "Workflow for every change"): the core team's pull
-# requests are checked locally on the crates they touch and merged; a red main is fixed forward.
+# CI runs once per merge on `develop`, the trunk (AGENTS.md, "Workflow for every change"): the core
+# team's pull requests are checked locally on the crates they touch and merged; a red trunk is
+# fixed forward. `main` holds released code only (docs/releasing.md).
 # Pull requests from forks (outside contributors) run the full gate, once the maintainer approves
 # the run, so the review sees it.
 on:
@@ -13,7 +14,7 @@ on:
       - 'docs/features.md'
       - 'docs/oracle.md'
   push:
-    branches: [main]
+    branches: [develop]
     # A merge that only touches prose starts no run. The generated pages are checked by the jobs
     # (features.md by `cargo xtask ci`, oracle.md by the oracle job), so they still count.
     # (Later patterns override earlier ones.)
@@ -24,7 +25,7 @@ on:
       - 'docs/features.md'
       - 'docs/oracle.md'
   schedule:
-    # Nightly: the heavy tests on main.
+    # Nightly, on the default branch (develop): the heavy tests.
     - cron: '23 3 * * *'
   workflow_dispatch:
 
@@ -54,7 +55,7 @@ jobs:
           targets: wasm32-unknown-unknown
       - uses: Swatinem/rust-cache@6323deb102c322ba6fcbdcafc7e3dddab59af2b6 # v2.9.2
         with:
-          save-if: ${{ github.ref == 'refs/heads/main' }}
+          save-if: ${{ github.ref == 'refs/heads/develop' }}
       - run: cargo xtask ci
 
   heavy:
@@ -68,7 +69,7 @@ jobs:
       - uses: dtolnay/rust-toolchain@stable
       - uses: Swatinem/rust-cache@6323deb102c322ba6fcbdcafc7e3dddab59af2b6 # v2.9.2
         with:
-          save-if: ${{ github.ref == 'refs/heads/main' }}
+          save-if: ${{ github.ref == 'refs/heads/develop' }}
       - run: cargo xtask test --heavy
 
   oracle:
@@ -85,7 +86,7 @@ jobs:
       - uses: Swatinem/rust-cache@6323deb102c322ba6fcbdcafc7e3dddab59af2b6 # v2.9.2
         with:
           key: oracle
-          save-if: ${{ github.ref == 'refs/heads/main' }}
+          save-if: ${{ github.ref == 'refs/heads/develop' }}
       - run: cargo xtask oracle
       - name: docs/oracle.md is current
         run: git diff --exit-code docs/oracle.md

.github/workflows/release.yml

@@ -1,11 +1,12 @@
 # Release builds (docs/releasing.md), after SolidCraft's and VectorCraft's release.yml
 # (MIT OR Apache-2.0; see ATTRIBUTION.md).
 #
-# A push to `release` (fast-forwarded from main) builds every package and creates or updates the
+# A push to `main` (fast-forwarded from a verified `develop` commit; main holds released code only)
+# builds every package and creates or updates the
 # DRAFT GitHub Release "FieldCraft v<version>", with SHA256SUMS.txt and generated notes. The
 # version is [workspace.package] version in Cargo.toml; a suffix (0.2.0-rc.1) makes a
 # pre-release. A person verifies the draft and publishes it; this workflow never publishes,
-# and pushes to main or tags never start it.
+# and pushes to develop or tags never start it.
 #
 #   macOS universal (arm64 + x86_64)   .dmg with FieldCraft.app, the CLI as a .zip   packaging/macos
 #   Linux x86_64 (glibc 2.35+)         .tar.gz and .AppImage                          packaging/linux
@@ -15,17 +16,17 @@
 # otherwise (the release notes say which). Linux and Windows builds are not signed.
 #
 # Dry run: `gh workflow run release.yml --ref <branch>` builds everything and uploads the
-# `release-assets` artifact without creating a release. `-f draft=true` on `release` retries
+# `release-assets` artifact without creating a release. `-f draft=true` on `main` retries
 # the draft.
 name: Release
 
 on:
   push:
-    branches: [release]
+    branches: [main]
   workflow_dispatch:
     inputs:
       draft:
-        description: "Create/update the draft release (release branch only; off: build artifacts only)"
+        description: "Create/update the draft release (main only; off: build artifacts only)"
         type: boolean
         default: false
 
@@ -60,8 +61,8 @@ jobs:
             echo "::error::Cargo.toml must contain a version like 1.2.3 or 1.2.3-rc.1, not '$VERSION'"
             exit 1
           fi
-          if [ "$REQUEST_DRAFT" = true ] && [ "$GITHUB_REF" != refs/heads/release ]; then
-            echo "::error::Draft releases are built from the release branch only"
+          if [ "$REQUEST_DRAFT" = true ] && [ "$GITHUB_REF" != refs/heads/main ]; then
+            echo "::error::Draft releases are built from main only"
             exit 1
           fi
           case "$VERSION" in *-*) pre=true ;; *) pre=false ;; esac
@@ -86,7 +87,7 @@ jobs:
         with:
           key: release-macos-universal
           # Release runs are rare: only release-branch runs keep a cache, so dry runs don't evict CI's.
-          save-if: ${{ github.ref == 'refs/heads/release' }}
+          save-if: ${{ github.ref == 'refs/heads/main' }}
       - name: Import the signing certificate (skipped without APPLE_CERTIFICATE)
         env:
           APPLE_CERTIFICATE: ${{ secrets.APPLE_CERTIFICATE }}
@@ -129,7 +130,7 @@ jobs:
         with:
           key: release-linux-x86_64
           # Release runs are rare: only release-branch runs keep a cache, so dry runs don't evict CI's.
-          save-if: ${{ github.ref == 'refs/heads/release' }}
+          save-if: ${{ github.ref == 'refs/heads/main' }}
       - name: Build and package (tar.gz, AppImage)
         run: packaging/linux/package.sh
       - name: Check the packages
@@ -167,7 +168,7 @@ jobs:
         with:
           key: release-windows-x64
           # Release runs are rare: only release-branch runs keep a cache, so dry runs don't evict CI's.
-          save-if: ${{ github.ref == 'refs/heads/release' }}
+          save-if: ${{ github.ref == 'refs/heads/main' }}
       - name: Build and package (zip)
         shell: pwsh
         run: ./packaging/windows/package.ps1