Release channels: publish pre-release bundles as catalog versions[] entries with a channel marker

[pofallon]

Context

Hola now supports release channels (try-hola/hola#428, ADR 0005 — https://github.com/try-hola/hola/blob/main/docs/adr/0005-release-channels.md, shipped in try-hola/hola#430 and #434). The server reads a channel marker on each catalog.json versions[] entry and lets a deployment follow a channel (stable by default, e.g. rc). Nothing on the server side is blocked, but the catalog cannot express a pre-release yet, so the feature is only reachable through custom catalog sources until this repo can publish one.

What the server reads (the contract)

{ "id": "remo",
  "versions": [
    { "version": "0.10.1",      "channel": "stable", "refs": { "oci": "ghcr.io/try-hola/remo:0.10.1" } },
    { "version": "0.11.0-rc.1", "channel": "rc",     "refs": { "oci": "ghcr.io/try-hola/remo:0.11.0-rc.1" } }
  ] }

• channel is optional; absent or null ⇒ stable.
• Grammar ^[a-z][a-z0-9-]{0,31}$. Any other value drops the entry (with a server warning) — it never defaults to stable, so a typo can't publish a pre-release as the default.
• A version string listed twice: the first well-formed occurrence wins.
• Ordering uses semver precedence with prerelease identifiers (1.3.0 > 1.3.0-rc.10 > 1.3.0-rc.9); the browse card and the default install always resolve to the newest stable entry.
• A channel only counts as a separate instance of a single-instance app when the catalog actually lists a version on it (Release channels: per-app-and-channel singleton guard is bypassable with any invented channel name hola#431).
• The bundle manifest.json is unchanged — the channel is a catalog-index attribute. "Deploy the rc" is a bundle pre-release (remo 0.11.0-rc.1 whose compose pins remo-web:4.4.0-rc.1 and whose manifest carries the matching upgrade metadata), never an image override.

Prerequisites in this repo (in dependency order, from try-hola/hola#428)

1. bin/push-oci-package.sh moves :latest unconditionally. It runs push "$VERSION" then push latest whenever TAG=latest, and TAG defaults to latest while build-and-publish.yml:108 passes only three arguments. Publishing an rc bundle would make it the default for every install. cli-release.yml in try-hola/hola already has the guard to copy:

   if [[ "$VERSION" == *-* ]]; then   # pre-release: do not move :latest

2. build-and-publish.yml only publishes on merge to main (github.event_name != 'pull_request') and regenerates catalog.json there, so getting an rc into the catalog is a production catalog change — circular. Pre-release-versioned bundles should be publishable from a PR.
3. build-catalog.sh needs to emit multiple versions[] entries per app with the channel marker (stable + any pre-releases still offered).
4. version-bump.yml and tag-release.yml are stale — both read packages/${package}/package.json, but the layout is src/<name>/ and there is no packages/ directory. They also offer only patch|minor|major, with no pre-release bump. Fix or delete.

Also worth folding in: validate-catalog should accept the optional channel field on versions[] entries and reject values outside the grammar above at publish time, so a bad marker fails CI here instead of being silently dropped by every server.

Acceptance

• An rc bundle can be published from a PR without touching :latest.
• catalog.json lists the stable and rc versions of the app side by side with channel markers.
• hola install <app> --channel rc --as <name> on a stock Hola install picks up the rc from the public catalog.

🤖 Generated with Claude Code

[pofallon]

Closing: delivered by #150 and proven by #151.

• bin/push-oci-package.sh never moves :latest for a pre-release; build-and-publish.yml publishes pre-release bundles from a PR; bin/build-catalog.sh emits multiple versions[] entries with a channel marker; version-bump.yml fixed for the real layout with pre-release bumps, tag-release.yml deleted; schemas/catalog.schema.json + bin/validate-catalog.mjs enforce the channel grammar in CI.
• First real exercise: feat(remo): 0.11.0-beta.2 — remo-web 4.4.0rc2 on the beta channel #151 published ghcr.io/try-hola/remo:0.11.0-beta.1 from the PR (latest unchanged), and the workflow_dispatch regeneration on main (run 33874829384) listed it via the live GHCR listing — catalog.json now carries remo 0.10.1 (stable) and 0.11.0-beta.1 (beta).
• Upstream image side: feat(ci): publish the remo-web image for a pre-release (rc-image.yml) get2knowio/remo#199 (rc-image.yml).

Docs: docs/release-channels.md.