feat(bootstrap): GH_TOKEN-based clone of Scrum4Me + scrum4me-mcp

Fixes the 'no GitHub credentials' deadlock observed in the first
NAS-Docker batch run (2 May 2026): scrum4me-mcp's `wait_for_job`
expects a local clone at `~/Projects/<repo-name>` (convention-fallback
in resolveRepoRoot) but the container had no credentials and no clone.
Agent asked the user how to proceed; turn closed without claim.

Changes:
- `.env.example`: GH_TOKEN (fine-grained PAT, repo+PR scope) and
  GH_PRECLONE_REPOS (comma-separated owner/name list, default covers
  Scrum4Me + scrum4me-mcp).
- `bin/repo-bootstrap.sh` (new): runs as agent-user; configures git
  credential-helper with HTTPS oauth2 token, then clones-or-fetches
  each entry in GH_PRECLONE_REPOS into ~/Projects/<name>. Idempotent.
- `bin/entrypoint.sh`: hooks repo-bootstrap before run-agent.sh.
- `Dockerfile`:
  - installs `gh` CLI (used for auto_pr `gh pr create`; reads GH_TOKEN
    from env directly).
  - pre-creates `~agent/Projects` and `~agent/.scrum4me-agent-worktrees`
    so directory-ownership is right from the first boot.
- `README.md`: 'Repo bootstrap (clone-on-start)' section + GH_TOKEN
  step in the deploy checklist; corrects the obsolete 'no push
  credentials' note (agent now pushes feature-branches, gh creates PRs).

Same token covers clone, push and PR-creation — one secret to rotate.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

bin/repo-bootstrap.sh

@@ -0,0 +1,68 @@
+#!/usr/bin/env bash
+# repo-bootstrap.sh — pre-clone repos into ~agent/Projects so that
+# scrum4me-mcp's `wait_for_job` finds a working repoRoot via the
+# convention-fallback `~/Projects/<name>/.git`.
+#
+# Idempotent:
+#   - Sets up git credential helper using GH_TOKEN (HTTPS auth)
+#   - For each entry in GH_PRECLONE_REPOS (comma-separated owner/name list):
+#       * If ~/Projects/<name> exists → `git fetch origin --prune`
+#       * Otherwise → fresh `git clone`
+#
+# Runs as the agent user (called from entrypoint.sh after `gosu agent …`).
+
+set -uo pipefail
+
+source /opt/agent/bin/_lib.sh
+
+: "${GH_TOKEN:=}"
+: "${GH_PRECLONE_REPOS:=}"
+
+if [[ -z "$GH_TOKEN" ]]; then
+    log "GH_TOKEN not set — skipping clone bootstrap. wait_for_job will fail until repos exist."
+    return 0 2>/dev/null || exit 0
+fi
+
+if [[ -z "$GH_PRECLONE_REPOS" ]]; then
+    log "GH_PRECLONE_REPOS empty — nothing to clone."
+    return 0 2>/dev/null || exit 0
+fi
+
+# ----- 1. configure git credential helper for HTTPS clone/push -----------
+mkdir -p "$HOME"
+git config --global credential.helper store
+CREDS_FILE="$HOME/.git-credentials"
+if [[ ! -f "$CREDS_FILE" ]] || ! grep -q "oauth2:${GH_TOKEN}@github.com" "$CREDS_FILE" 2>/dev/null; then
+    printf 'https://oauth2:%s@github.com\n' "$GH_TOKEN" > "$CREDS_FILE"
+    chmod 600 "$CREDS_FILE"
+    log "git credentials helper configured at ${CREDS_FILE}"
+fi
+
+# Prevent the token from leaking into commit-author of automated commits.
+git config --global user.name "${GIT_AUTHOR_NAME:-Scrum4Me Agent}"
+git config --global user.email "${GIT_AUTHOR_EMAIL:-agent@scrum4me.local}"
+
+# ----- 2. clone-or-fetch each repo --------------------------------------
+mkdir -p "$HOME/Projects"
+
+IFS=',' read -ra REPOS <<< "$GH_PRECLONE_REPOS"
+for repo in "${REPOS[@]}"; do
+    repo=$(echo "$repo" | tr -d '[:space:]')
+    [[ -z "$repo" ]] && continue
+
+    name=$(basename "$repo")
+    target="$HOME/Projects/$name"
+
+    if [[ -d "$target/.git" ]]; then
+        log "fetching ${repo} into ${target}"
+        git -C "$target" fetch origin --prune --quiet \
+            || log "WARN: fetch failed for ${repo} (continuing)"
+    else
+        log "cloning ${repo} into ${target}"
+        rm -rf "$target"
+        git clone --quiet "https://github.com/${repo}.git" "$target" \
+            || { log "ERROR: clone failed for ${repo}"; continue; }
+    fi
+done
+
+log "repo-bootstrap done"