chore(release): 1.2.0-rc.1

[fujibee]

The version bump for the first prerelease this project has cut. Three files,
nothing else.

Why 1.2.0-rc.1

integration/remote carries 430 commits main does not — remote sync, the
server, e2ee, the handoff bundle. That is a minor, not a patch.

Not 1.1.13-rc.1: under semver a prerelease orders before its release, so
that string would sort earlier than the 1.1.13 already published as latest.

1.1.13  <  1.2.0-rc.1  <  1.2.0

What the tag will do, and what it will not

release.yml derives both prerelease decisions from the hyphen in the version
rather than from whoever pushes the tag:

• npm dist-tag next, so npm install agmsg keeps giving people 1.1.13
• gh release create --prerelease, so the repository's front page keeps
  offering 1.1.13 as the latest release

npm view agmsg dist-tags is { latest: '1.1.13' } today — there is no next
yet, and no prerelease tag has ever existed here. This will be the first run
of that branch of the workflow. Its logic was exercised locally in both
directions (1.2.0 → latest, 1.2.0-rc.1 → next --prerelease), but the
workflow itself has never taken that path. The production environment gates
the publish behind a required reviewer, so the printed dist_tag can be read
before anything reaches npm.

What is not bumped, deliberately

sync-version.sh owns VERSION, package.json and
.claude-plugin/plugin.json. These other occurrences of a version string stay:

where	what it is
CHANGELOG.md [1.1.11] heading and link	a record of a release that happened
.github/workflows/release.yml:57	"As of 2026-08-07 npm view agmsg dist-tags is { latest: 1.1.13 }"
tests/test_release_dist_tag.bats ×2	the same observation, in the tests that pin it

The last three are observations with a date attached. Bumping a record makes it
false, and it becomes a second place someone has to remember to bump.

Not included

main has moved one commit past the merge base this branch picked up — #654
(doctor defaults). It is not in this rc. Nothing else in main is missing:
#657 landed the other 16 fixes and the sweep is in that PR.

Verification

• sync-version.sh --check passes, which is the gate the release workflow runs
  before publishing; a mismatch there fails the tag rather than shipping.
• The diff is three files. Confirm that before approving the tag — an earlier
  attempt at this commit picked up an untracked .envrc and a worktree gitlink
  through git add -A, and was rebuilt from the base rather than amended.