fix(opencode): require an http(s) baseURL in both OpenCode plugins

[maxmad64bis]

⚠️ base-red inherited: #12732

Summary

Type your gateway address without http:// and the plugin accepts it, then nothing works.

z.string().url() accepts anything new URL() parses, and new URL() reads localhost:20128 as the scheme localhost: followed by a path. Both OpenCode plugins take it, publish every model with localhost:20128/v1 as its api url, and every call then fails inside the client on an unknown scheme. No request is sent, so the gateway logs show nothing and the error names neither the option nor a model.

Only host:port slips through — or.example.com/v1 is already rejected — which is the local address almost every install starts with.

Both plugins now trim the value and require an http(s) scheme, the same treatment headroomUrl already gets in src/shared/validation/settingsSchemas.ts, where the comment spells out why z.string().url() is not enough on an address that ends up in fetch. Inside the v2 plugin a single isHttpUrl backs the option schema, the publish boundary (legacyApiToInfoApi) and the snapshot filter (isStaleSnapshotModel), which previously accepted a card with a blank or relative url — those three cannot drift apart. The v1 plugin carries its own copy of the predicate, since the two packages ship independently and neither depends on the other.

Related Issues

• No open issue tracks this.
• Related to 🔴 Release branch not green: release/v3.8.51 #12732 — the base is red independently of this change.

Validation

• Change type: provider / routing / UI / i18n / CLI / DB / build-deploy / other
• Focused tests and category gates from the golden path
• npm run lint
• Reconciled with the current active release base; focused checks rerun afterward
• Production-code changes include a new or updated automated test in this PR

Tests Added Or Updated

• @omniroute/opencode-plugin/tests/options-schema.test.ts and @omniroute/opencode-plugin-v2/tests/options.test.ts — scheme-less, ftp:// and bare-host addresses rejected with the new message; http(s) accepted, padding trimmed.
• @omniroute/opencode-plugin-v2/tests/snapshot-stale-entries.test.ts — a snapshot entry with a package but no url is dropped and counted in the warning; blank, relative and non-http urls rejected at the publish boundary.
• docs/guides/OPENCODE-V2-PLUGIN.md — the baseURL row now states the http(s) requirement.

Coverage Notes

• Touches src/index.ts in @omniroute/opencode-plugin, and src/options.ts, src/catalog.ts, src/cache.ts, src/shared/models-map.ts in @omniroute/opencode-plugin-v2. Neutering isHttpUrl turns three v2 cases red, one per site; removing either plugin's schema guard turns its own case red.

Reviewer Notes

• This is a tightening: a configuration accepted today stops being accepted. It never worked — it failed on every call with an error that named nothing. A clear message at startup replaces a catalog of unusable models.
• The three red checks on this head are inherited, not from this branch:
  • No new ESLint warnings — 🔴 Release branch not green: release/v3.8.51 #12732 states ratchet drift (eslint warnings, cognitive complexity, file size) is expected mid-cycle, rebaselined at release, and not a contributor concern. ESLint is clean on the five files this PR changes.
  • Merge integrity (changelog + generated skills) — 🔴 Release branch not green: release/v3.8.51 #12732 lists check:agent-skills-sync among the base failures.
  • Docs Gates (fast-path) — check:docs-counts reports three stale migration counts, in README.md, AGENTS.md and llm.txt. This PR touches none of them; the only doc it changes is the plugin guide.
• npm run lint is left unchecked for the same reason: the repo gate is red on this base for three no-explicit-any errors in tests/unit/volcengine-plan-binding-upsert.test.ts, untouched here.
• Run each package suite with its own npm test: v2 is 222/222; v1 is 368/369, where scaffold.test.ts imports a built dist/ the tree does not carry and fails the same way on an untouched checkout.