P2 wave 1: extract concerns from pumpingStation specificClass

Splits pumpingStation/src/ into focused concern modules. specificClass.js
will be slimmed to an orchestrator in P2.9 (integration); for now both
the inlined logic AND the new modules coexist so tests stay green
throughout.

  src/basin/         BasinGeometry + thresholdValidator (pure)
  src/measurement/   flowAggregator + measurementRouter + calibration
  src/control/       levelBased + flowBased(stub) + manual + index dispatcher
  src/safety/        safetyController split into dryRun + overfill rules
  src/commands/      registry array + handlers (canonical names from start)
  src/editor.js      260 lines of SVG basin-diagram redraw, was inline in .html
  examples/standalone-demo.js  was if(require.main===module) at bottom of specificClass.js
  CONTRACT.md        canonical inputs + outputs + emitted events

Modified:
  src/specificClass.js  removed the 170-line standalone demo block
  pumpingStation.html   oneditprepare/oneditsave delegate to editor.{init,save}
  pumpingStation.js     added admin endpoint serving src/editor.js

102 basic tests pass (60 new + 42 existing).
specificClass.js itself is unchanged in behaviour — integration is P2.9.

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

src/control/index.js

@@ -0,0 +1,20 @@
+const levelBased = require('./levelBased');
+const flowBased = require('./flowBased');
+const manual = require('./manual');
+
+const strategies = {
+  [levelBased.name]: levelBased,
+  [flowBased.name]: flowBased,
+  [manual.name]: manual,
+};
+
+function dispatch(mode, ctx, controlState) {
+  const s = strategies[mode];
+  if (!s) {
+    ctx.logger?.warn?.(`Unsupported control mode: ${mode}`);
+    return Promise.resolve();
+  }
+  return s.run(ctx, controlState);
+}
+
+module.exports = { strategies, dispatch, manual };