ALEC-307: Migrate the ALEC UI to Onms Vue components

[joseanesONMS]

Jira: https://opennms.atlassian.net/browse/ALEC-307

Rewrites the ALEC plugin UI from FeatherDS to the OpenNMS Onms-* component stack so it renders natively on the OpenNMS 37 Vue UI and stays self-contained on Feather-based hosts (Meridian, OpenNMS ≤36).

• @opennms/onms-ui is private/workspace-only today, so the 35 wrappers are vendored (pinned to opennms develop 5ebe7e2c828) behind an @opennms/onms-ui alias the published package can later replace as a drop-in.
• ui/src/theme/primevue-host.ts bridges bundled PrimeVue to whichever host mounts the plugin: on a PrimeVue host the live host config drives theme and dark mode; on a Feather host the vendored OpenNMS preset self-installs (the host app renders ALEC's root, so app.use() is never available to a plugin).
• All 30 screens/components are migrated — FormField-wrapped fields, Info-icon help affordances, useOnmsToast, and the shared severity classes — and FeatherDS is fully removed (28 packages, the ALEC-306 CSS stopgap, variables.scss).
• ESLint now errors on primevue/* and @featherds/* imports outside the seam, mirroring the host rule; the UI toolchain is aligned with the host (TS 5.5, vue-tsc 3.3, Vue 3.5 types — runtime still resolves to the host globals).
• Verified on a live OpenNMS 37 in light and dark mode; 86/86 unit tests and 0 lint errors.

[synqotik]

Most of these files (e.g. anything in ui/components or onms-ui) should not have been added.

The Feather components should be rewritten using the onms-ui package, however the actual onms-ui code and implementation should not be in this codebase. After compilation, when you actually run it against an OpenNMS instance, the code will wire up at runtime.

If this doesn't make sense, or isn't working, let me know, I'm happy to take a look myself.

[joseanesONMS]

We will create a branch for an alec 4.0 that will be compatible with Meridian 26+. This ticket will go into that branch.

Current claude findings in response to current concerns:
What the host actually provides

I checked the opennms checkout to confirm the reviewer's premise, and it holds.

• The host main bundle assigns the whole onms-ui barrel to window.OnmsUI before mounting, alongside window.Vue, Pinia, and VueRouter. It shipped in NMS-20054 and is in every build from 36.0.3 onward and in release-36.x. It is not in foundation-2025.
• The documented plugin contract lives in ui/packages/onms-ui-example-plugin/. It externalizes @opennms/onms-ui to window.OnmsUI with rollup-plugin-external-globals, producing an ES module exactly like ALEC's build target.
• Every name ALEC imports from the barrel exists in the host barrel today, including the toast composable. The screen migration itself does not need to change.

What has to come out of the branch

• The 35 vendored seam components, the composable, the directive, and the alias in three vite configs plus tsconfig. Roughly 3,100 vendored lines.
• The PrimeVue host bridge, the vendored OpenNMS theme preset, and the copied --onms-* token stylesheets. The host already provides theme, dark mode, and those tokens globally. The primevue and @primevue/themes dependencies go with them.
• The Feather-host fallback path. That is a deliberate loss: the PR description promises Meridian and OpenNMS 36 or older, and Meridian 2025 has no window.OnmsUI. The minimum host becomes 36.0.3. That is your call, but it is where the reviewer's direction leads.

Three gaps the reviewer's message does not cover

• Icons. The host README states subpath icon imports are not on window.OnmsUI and need the package resolvable at build time, which a private package is not. It explicitly names vendoring as the current answer for external plugins. ALEC uses 25 icons. FormField and HelpBadge are core-app files, not in the barrel at all. Those copies may need to stay, and that is worth raising on the PR.
• Types. With the package unpublished, vue-tsc has nothing to check against. The options are a checked-in declarations file generated from the opennms package, or an ambient declare module shim that loses type safety. I would recommend the generated declarations.
• Unit tests. The situation and configuration tests mount real components, and vitest currently resolves the alias to the vendored copy. Without it, tests need either a stub module for @opennms/onms-ui or a dev-time path to an opennms checkout, which does not work in CI.