Clarify tooltip: setting takes effect on next build, not requiring Clean

The preference is applied to the live workspace immediately via
ws.setProperty(), so changes take effect on the next build without
requiring a clean.

Author: Copilot

bndtools.core/src/bndtools/preferences/ui/BndBuildPreferencePage.java

@@ -56,7 +56,7 @@ protected Control createContents(Composite parent) {
 		cmbRebuildPolicy.setItems("Always rebuild", "API-based (skip if API unchanged)");
 		cmbRebuildPolicy.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, true, false));
 		cmbRebuildPolicy.setToolTipText(
-			"Controls when Eclipse triggers rebuilds: Always rebuild on any change, or skip rebuilds when only internal (non-API) changes are detected. A full workspace build (Project > Clean...) is required for this setting to take effect.");
+			"'Always rebuild' triggers a rebuild on every change. 'API-based' skips rebuilds when only non-API changes are detected. Changes take effect on the next build.");
 		lblRebuildPolicy.setToolTipText(cmbRebuildPolicy.getToolTipText());
 
 		// Load Data