CLI: support package-manager installs from GitHub main (#47630)

* CLI: resolve package-manager main install specs

* CLI: skip registry resolution for raw package specs

* CLI: support main package target updates

* CLI: document package update specs in help

* Tests: cover package install spec resolution

* Tests: cover npm main-package updates

* Tests: cover update --tag main

* Installer: support main package targets

* Installer: support main package targets on Windows

* Docs: document package-manager main updates

* Docs: document installer main targets

* Docs: document npm and pnpm main installs

* Docs: document update --tag main

* Changelog: note package-manager main installs

* Update src/infra/update-global.test.ts

Co-authored-by: greptile-apps[bot] <165735046+greptile-apps[bot]@users.noreply.github.com>

---------

Co-authored-by: greptile-apps[bot] <165735046+greptile-apps[bot]@users.noreply.github.com>

docs/cli/update.md

@@ -21,6 +21,7 @@ openclaw update wizard
 openclaw update --channel beta
 openclaw update --channel dev
 openclaw update --tag beta
+openclaw update --tag main
 openclaw update --dry-run
 openclaw update --no-restart
 openclaw update --json
@@ -31,7 +32,7 @@ openclaw --update
 
 - `--no-restart`: skip restarting the Gateway service after a successful update.
 - `--channel <stable|beta|dev>`: set the update channel (git + npm; persisted in config).
-- `--tag <dist-tag|version>`: override the npm dist-tag or version for this update only.
+- `--tag <dist-tag|version|spec>`: override the package target for this update only. For package installs, `main` maps to `github:openclaw/openclaw#main`.
 - `--dry-run`: preview planned update actions (channel/tag/target/restart flow) without writing config, installing, syncing plugins, or restarting.
 - `--json`: print machine-readable `UpdateRunResult` JSON.
 - `--timeout <seconds>`: per-step timeout (default is 1200s).