feat: scenarios for curator/memo-inbox/pi-grok, deploy and backup tooling

Scenarios
- memo-inbox: mirrored by copying; the live directory was not moved or modified
  and the service was not restarted. All four tracked files match byte for byte
  (pi-diff.sh reports SAME). Marked deploy = "mirror" so deploy-scenario.sh
  refuses --apply: applying a mirror would invert the direction of truth and
  could change a service in daily use.
- curator: target configuration, not yet deployed. .pi/SYSTEM.md replaces pi's
  coding-assistant prompt; durable role text is in .pi/APPEND_SYSTEM.md;
  profile.toml is the single source of truth for the launch contract.
- pi-grok: registered only. It is genuinely a coding agent, so the isolation
  baseline does not apply in full.

Corrections to the documentation, found by testing rather than by reading
- AGENTS.override.md does NOT block parent-directory context files; it only
  shadows its own directory. Verified: with an override file in the workspace, a
  marker in /tmp/AGENTS.md still reached the system prompt. The only effective
  switch is --no-context-files, so durable role text must live in
  .pi/APPEND_SYSTEM.md, which is a system-prompt file and unaffected by -nc.
  Verified end state: no coding-assistant framing, no pi-docs block, own
  identity and role text present, no parent pollution, only own skills/tools.
- PI_CODING_AGENT_DIR isolates settings/models/auth/trust/extensions/skills/
  prompts/themes under the agent directory -- stronger than the --no-* flags
  because it also repoints credentials -- but does NOT cover ~/.agents/skills.
  Measured: find-skills, modsearch and summarize still leak. So it complements
  --no-skills rather than replacing it.
- --append-system-prompt accepts a file path, which pi-grok relies on.
- cwd is what anchors .pi discovery: a probe that forgot cwd silently lost
  .pi/SYSTEM.md and kept the coding-assistant persona.

Tooling (all dry-run by default; none of them restarts a service)
- pi-diff.sh: compares tracked config against the live install in both
  directions, with a key-redacted comparison for models.json
- deploy-scenario.sh: installs a workspace and renders profile.toml into
  .pi/launch.json, then checks that every referenced path exists
- deploy-runtime.sh: renders models.json from its template, refusing placeholder
  or missing keys. Verified byte-identical to the live file
- pi-backup.sh / pi-restore.sh: archives outside the repo, sha256 manifest
  verified before any restore, live paths preserved rather than overwritten

Fixed while testing: pi-backup.sh compared the destination against the repo root
literally, so a relative --dest ./backups wrote credential archives into the work
tree. Now canonicalised with realpath; ./backups, an absolute in-repo path and
./docs/../backups are all refused.

scenarios/memo-inbox/workspace/bin/journal-sync.sh

@@ -0,0 +1,37 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+if [[ "$#" -ne 1 ]]; then
+  echo "usage: journal-sync.sh journals/YYYY_MM_DD.md" >&2
+  exit 64
+fi
+
+rel="$1"
+if [[ ! "$rel" =~ ^journals/[0-9]{4}_[0-9]{2}_[0-9]{2}\.md$ ]]; then
+  echo "refusing non-journal path: $rel" >&2
+  exit 65
+fi
+
+vault="${PI_MEMO_VAULT:-$HOME/obsidian-vault}"
+lock="$HOME/.local/state/obsidian-sync/git-sync.lock"
+mkdir -p "$(dirname "$lock")"
+exec 9>"$lock"
+flock -w 30 9
+
+cd "$vault"
+git add -- "$rel"
+if git diff --cached --quiet -- "$rel"; then
+  echo "no journal changes to commit"
+  exit 0
+fi
+
+git commit -m "journal: Pi Memo $(date +%Y-%m-%d-%H%M)" -- "$rel"
+
+# The host's system SSH config may be managed outside this service. Keep the
+# memo sync self-contained so unrelated ownership errors cannot block pushes.
+export GIT_SSH_COMMAND="ssh -F $HOME/.ssh/config -i $HOME/.ssh/id_ed25519_gitea -o IdentitiesOnly=yes -o StrictHostKeyChecking=accept-new"
+if ! git push origin main; then
+  git pull --rebase origin main
+  git push origin main
+fi
+echo "pushed $(git rev-parse --short HEAD)"