(feat): add Split Dev workflow for publishing feature-branch splits

[ChiragAgg5k]

What

Adds a manually dispatched Split Dev workflow that publishes a feature branch's split of one or more packages to their read-only mirrors, restoring the pre-monorepo unblock flow: a consumer (e.g. Appwrite) can composer require utopia-php/<name>:dev-<branch> from Packagist before the branch is merged or released.

How

• Actions → Split Dev → Run workflow on the feature branch, with inputs package (space-separated names) and action (publish | delete).
• publish reuses the existing bin/monorepo split <pkg> --branch=<branch> --force with the same split-app token as the regular Split workflow — no bin/monorepo changes needed. --force because rebases change the synthesized split history.
• delete removes the mirror branch once the work merges or is abandoned.
• The run summary prints a copy-pasteable consumer requirement, aliasing into the latest released minor (dev-my-branch as 2.0.999) so sibling constraints keep resolving; unreleased packages fall back to plain dev-<branch>.
• Refuses to run on main (that's the regular Split's job). Mirror rulesets only target the default branch, so dev branches need no ruleset changes.
• Docs: new "Dev branches" section in docs/distribution.md, pointer in the README's cross-package section.

Verification

• Workflow YAML parses.
• bin/monorepo split http di --branch=test-branch --dry-run synthesizes both split heads.
• Summary alias snippet tested for released (http → as 2.0.999) and unreleased (nats) packages.
• Needs one live dispatch post-merge to confirm the app token creates mirror branches and Packagist picks them up.

[greptile-apps]

Greptile Summary

This PR adds a manually-dispatched Split Dev workflow that lets contributors push a feature branch's package split to the mirror repos, enabling external consumers to composer require utopia-php/<name>:dev-<branch> before the branch is merged or released.

• New workflow (.github/workflows/split-dev.yml): supports publish (calls bin/monorepo split ... --force) and delete (removes the mirror branch via refspec deletion); the delete loop uses if/else to continue past individual failures and exits non-zero only if at least one deletion failed. The run summary generates a copy-pasteable inline-alias requirement, filtering pre-release tags with grep -v -- - before computing the alias.
• Docs/README: a new "Dev branches" section in docs/distribution.md documents the dispatch flow, inline-alias rationale, force-push requirement, and cleanup steps; README.md adds a short pointer.

Confidence Score: 5/5

Safe to merge — the workflow is additive, touches no existing logic, and is manually dispatched only by users with write access.

The implementation is self-contained and consistent with the existing split.yml patterns (pinned SHA actions, SPLIT_REMOTE_BASE env var for token, persist-credentials: false). The delete loop correctly uses if/else to survive partial failures without triggering bash exit-on-error, and the version-alias logic filters pre-release tags before computing the alias. No existing workflows or release paths are affected.

No files require special attention.

Important Files Changed

Filename	Overview
.github/workflows/split-dev.yml	New manually-dispatched workflow for publishing/deleting feature-branch splits to mirror repos; delete loop uses if/else to survive partial failures, version aliasing filters pre-releases with grep -v, all well-structured
README.md	Adds one-line pointer to Split Dev workflow for external consumers needing an unmerged branch
docs/distribution.md	New Dev branches section documents the dispatch flow, inline-alias pattern, force-push rationale, and cleanup steps accurately

_{Reviews (2): Last reviewed commit: "(fix): harden split-dev delete loop and ..." | Re-trigger Greptile}