feat(telemetry-separation): dedicated /telemetry tab split from /events by adapter data_class (v0.7.4)

PR #5 of the v0.7.x GUI rework arc. Production code; central-gui restart only
(supervisor untouched -- data_class is read only by central-gui per request).

- SourceAdapter gains a `data_class` class attr (Literal["event","telemetry"],
  default "event"). NWIS opts in as "telemetry" (continuous high-volume water
  gauges); every other adapter stays "event". The /events vs /telemetry split is
  thus registry-derived from class attrs -- no hardcoded adapter-name lists.
- routes.py refactor: `_class_adapter_names(data_class)` and a `data_class` arg
  on `_adapter_filter_options` scope the flat + domain-grouped chip/legend lists
  to a class (colors stay keyed to the FULL registry, so an adapter keeps one
  color across tabs). `_fetch_events` accepts `class_adapters` and adds an
  `adapter = ANY(...)` condition. Shared `_events_query`, `_events_page(data_class,
  base_path)` and `_events_rows_fragment(...)` back both tabs; `/events`,
  `/events/rows`, `/telemetry`, `/telemetry/rows` are thin wrappers.
- Templates parameterized with a `base_path` context var (form action, hx-get,
  hx-push-url header, clear-all redirect, JS BASE_PATH const); the `_events_rows`
  paginator macro takes `base`. Same templates serve both tabs; nav gains a
  Telemetry link.
- /events.json UNCHANGED -- the cursor path sets no `class_adapters`, so the
  subject + pagination contract is intact (TestEventsJsonSubject still passes).

Adds TestTelemetrySeparation (data_class defaults, registry split 11 event / 1
telemetry, class-scoped filter options, color stability, and the `adapter =
ANY(...)` SQL shape incl. the no-class events.json path). Updates the events
frontend tests for the base_path-parameterized templates.

Full suite: 682 passed, 1 skipped (central and unprivileged zvx, 3x each).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

docs/PRODUCER-INTEGRATION.md

@@ -211,6 +211,7 @@ Optional class attributes (default to `None` / not-in-wizard):
 | `requires_api_key` | `str \| None` | Key alias if an API key is required, else `None`. |
 | `api_key_field` | `str \| None` | Names the `settings_schema` field that holds the api_key alias reference. The GUI renders this as a select populated from `config.api_keys`; the wizard validates it against the staged `api_keys` state. |
 | `wizard_order` | `int \| None` | Position in the setup wizard. `None` excludes the adapter from the wizard. |
+| `data_class` | `Literal["event", "telemetry"]` | GUI classification. `"event"` (default) = discrete events, shown on `/events`. `"telemetry"` = continuous/high-volume feeds (e.g. NWIS) shown on `/telemetry` instead, so they don't drown discrete-event signal. GUI-only — does not affect publishing or the `events.json` contract. |
 
 ### 4.2 Required methods