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>

pumpingStation.js

@@ -37,4 +37,16 @@ module.exports = function(RED) {
     }
   });
 
+  // Editor.js — extracted SVG basin-diagram + oneditprepare/oneditsave logic.
+  RED.httpAdmin.get(`/${nameOfNode}/editor.js`, (req, res) => {
+    try {
+      const fs = require('fs');
+      const path = require('path');
+      const script = fs.readFileSync(path.join(__dirname, 'src/editor.js'), 'utf8');
+      res.type('application/javascript').send(script);
+    } catch (err) {
+      res.status(500).send(`// Error loading editor.js: ${err.message}`);
+    }
+  });
+
 };