Add a release-execution skills root (pre_build)

skills/pre_build/pre_build.md

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+# Pre-Build: Format, Generate, Push, Dispatch
+
+Prepare all workspace repositories for a release build, then dispatch the GitHub Actions release workflow. This skill is a thin wrapper around `PyAutoBuild/bin/autobuild pre_build`, mirroring the pattern used by `/verify_install`.
+
+A **PyAutoBuild (Hands)** skill — Build is the release/packaging executor, and
+this is a **release-execution** entry point (format → generate → push →
+dispatch). It is the one skill class PyAutoBuild's `skills/` root hosts; Build
+owns **no** dev-workflow skills (`ship_*` live in PyAutoBrain and only *call*
+this release step). Readiness is gated upstream by Heart before a release is
+dispatched.
+
+## Steps
+
+### 1. Validate environment
+
+Check that all required repositories exist under the workspace root:
+- `autofit_workspace`
+- `autogalaxy_workspace`
+- `autolens_workspace`
+- `autofit_workspace_test`
+- `autogalaxy_workspace_test`
+- `autolens_workspace_test`
+- `euclid_strong_lens_modeling_pipeline`
+- `HowToGalaxy`
+- `HowToLens`
+- `HowToFit`
+- `PyAutoBuild`
+
+For each, verify:
+```bash
+git -C <repo> branch --show-current
+git -C <repo> status --short
+```
+
+All workspaces must be on `main`. If any are on a feature branch or have uncommitted changes, **stop and warn the user** — the pre-build expects clean `main` branches.
+
+Then ask the user for the minor version number (default: 1).
+
+### 2. Run `autobuild pre_build`
+
+Invoke the bash entry point directly:
+
+```bash
+bash $HOME/Code/PyAutoLabs/PyAutoBuild/bin/autobuild pre_build <minor_version>
+```
+
+The script handles every mechanical step of the pre-build flow:
+
+1. Ensures the canonical `pending-release` label exists on each release-window repo.
+2. For every workspace, runs `black .`, bumps the README version pin (`<Package> vYYYY.M.D.<minor>`) where applicable, runs `generate.py` for projects with a notebook target, and stages only the safe directories (`config/`, `notebooks/`, `scripts/`, `dataset/`, plus `slam_pipeline/` for `autolens_workspace`).
+3. Commits and pushes each workspace (skipping if no changes are staged).
+4. Commits and pushes PyAutoBuild itself.
+5. Dispatches `gh workflow run release.yml --repo PyAutoLabs/PyAutoBuild --field minor_version=<N>`.
+
+Release-readiness — including the version-skew check that used to run here
+(`verify_workspace_versions.sh`) — is gated **upstream by PyAutoHeart**
+(`pyauto-heart readiness`) before `pre_build` is invoked, not by this step. Build
+is a pure executor.
+
+If the script exits non-zero, surface the failure to the user verbatim and stop. Do not attempt to retry or repair — the script's preconditions (`set -e`) ensure that any non-zero exit reflects a real problem (lint failure, push rejected, workflow dispatch error).
+
+### 3. Summary
+
+When the script completes successfully, fetch and display the dispatched run URL:
+
+```bash
+gh run list --workflow=release.yml --repo PyAutoLabs/PyAutoBuild --limit 1 --json url --jq '.[0].url'
+```
+
+Then display:
+```
+Pre-Build Complete
+==================
+Minor version: <N>
+Workflow dispatched: <URL>
+
+The release workflow is now running. Use /review_release tomorrow
+to assess the results.
+```
+
+## Notes
+
+- The same operation is callable from the shell as `autobuild pre_build <minor>` (or `autobuild-help pre_build` for documentation). Use this skill when you want the Claude validation + summary wrapper; use the bash CLI when you just want to fire off the build.
+- README version-bump is now handled inside `pre_build.sh` (it used to live only in this skill).