v1.12.2.0 fix: /setup-gbrain day-two fixes (MCP scope, version parse, gh repo create order, smoke test) (#1187)

* fix: parse gbrain --version without "gbrain" prefix

Installer's D19 PATH-shadow check compared `expected_version` from
package.json against `actual_version` from `gbrain --version`. The
output is "gbrain 0.18.2" with a literal prefix; `tr -d '[:space:]'`
left "gbrain0.18.2" which never matched "0.18.2", causing every
fresh install to exit 3 with a false-positive shadowing error.

Use `awk '{print $NF}'` to grab just the last whitespace-separated
token before stripping whitespace.

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

* fix(brain-init): drop --source flag before git init

gstack-brain-init used `gh repo create --source $GSTACK_HOME` before
running `git init` on that directory. gh requires --source to point at
an existing git repo, so the call fails with "not a git repository"
on first run. The fallback path (gh repo view) could only recover if
the repo was somehow pre-created — which it wasn't.

Fix: omit --source from `gh repo create`. The script's later steps
(git init, remote add, push) wire up the remote explicitly.

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

* fix(setup-gbrain): smoke test command + MCP user scope with absolute path

Three Step 5a/9 defects found running /setup-gbrain end-to-end:

1. Step 9 smoke test used `gbrain put_page --title ... --tags ...`,
   which doesn't exist. The real command is `gbrain put <slug>` with
   body piped on stdin. Updated to match.

2. Step 5a registered MCP with `claude mcp add gbrain -- gbrain serve`.
   Default scope is local (per-workspace), so other projects never saw
   gbrain. Cross-session memory is the whole point — user scope is
   correct.

3. Step 5a passed `gbrain` by bare name, relying on PATH being resolved
   when Claude Code spawns the subprocess. Fragile across shell configs.
   Use absolute path from `command -v gbrain` with ~/.bun/bin/gbrain
   fallback.

Also: remove any stale local-scope registration before re-adding, and
tell the user that open Claude Code sessions need a restart to see
the new mcp__gbrain__* tools (loaded at session start, not mid-session).

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

* chore: bump version and changelog (v1.12.1.0)

Also updates test/gstack-brain-init-gh-mock.test.ts to match the fixed
behavior of bin/gstack-brain-init (the assertion previously required
`--source`, which was the bug being fixed in 04185d8f).

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

* docs: tighten CHANGELOG entry for v1.12.1.0

Shorter, matter-of-fact list of the fixes. No preamble.

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

---------

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

bin/gstack-brain-init

@@ -86,7 +86,10 @@ if [ -z "$REMOTE_URL" ]; then
     read -r REPLY || REPLY=""
     if [ -z "$REPLY" ]; then
       echo "Creating GitHub repo: $DEFAULT_NAME ..."
-      if ! gh repo create "$DEFAULT_NAME" --private --description "gstack session memory" --source "$GSTACK_HOME" 2>/dev/null; then
+      # Note: --source omitted intentionally. gh requires --source to point at
+      # an existing git repo, but we don't init $GSTACK_HOME until after the
+      # remote is chosen. Create bare, then fetch URL.
+      if ! gh repo create "$DEFAULT_NAME" --private --description "gstack session memory" 2>/dev/null; then
         # Maybe the repo already exists; try to fetch its URL.
         REMOTE_URL=$(gh repo view "$DEFAULT_NAME" --json sshUrl -q .sshUrl 2>/dev/null || echo "")
         if [ -z "$REMOTE_URL" ]; then