olt: add bulk DHCPv4/DHCPv6 filter edit alongside flood mode

Generalises the OLT bulk tool from flood-mode-only to arbitrary NNI-service
edits. DHCP modes live nested under each NNI entry's Filter object
(Filter.DHCPv4 / Filter.DHCPv6, e.g. "pass" <-> "umt"), confirmed from a
real OLT-CFG paste-back.

- src/mcms-api.js: planFloodChange -> planNniEdit(oltCfg, {tagPattern, flood,
  dhcpv4, dhcpv6}); each concern optional. DHCP is value-replacement,
  replace-only-when-present (never invents the key; leaves EAPOL/PPPoE/NDP).
  Still non-mutating (clones the entry AND the Filter). Returns changes with
  per-entry edits[]. summarizeOltNniNetworks surfaces dhcpv4/dhcpv6; new
  dhcpModeOfNni helper.
- main.js + web/server.js: executeFloodChange handler passes flood/dhcpv4/
  dhcpv6 ops through (channel name kept for wire compat).
- renderer: OLT inspector now has three action dropdowns (Flooding / DHCPv4 /
  DHCPv6, defaults flood private->auto + DHCP pass->umt); table shows DHCP
  chips + per-service "will change (flood, DHCPv4, …)"; flood-mode filter
  defaults to Any so DHCP-on-pass auto-flood OLTs still show; CSV report
  lists every per-NNI edit (pon-olt-nni-*.csv).

Verified: node --check; planNniEdit unit-tested against the real fixture +
a pass variant (13/13: no-mutation, EAPOL/PPPoE/NDP preserved,
replace-when-present, flood/DHCP independence); OLT view rendered offscreen
showing correct per-service "will change" markers.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

main.js

@@ -10,7 +10,7 @@ const path = require('path');
 const fs = require('fs');
 const {
   McmsClient, McmsApiError, extractOnuHealth,
-  summarizeOltNniNetworks, planFloodChange,
+  summarizeOltNniNetworks, planNniEdit,
 } = require('./src/mcms-api');
 const { summarizeDashboard } = require('./src/dashboard');
 const { planUpgrade, activeBankPtr, inactiveBank } = require('./src/bank-strategy');
@@ -654,9 +654,11 @@ ipcMain.handle('api:listOlts', async (_ev, opts) => {
 });
 
 /**
- * Apply a planned flooding mode change to a list of OLT IDs. For each
- * OLT we GET the current CFG (to avoid stomping concurrent edits),
- * run planFloodChange, and PUT the result back. Streams progress.
+ * Apply a set of NNI-service edits (flood mode and/or DHCPv4/DHCPv6 filter)
+ * to a list of OLT IDs. For each OLT we GET the current CFG (to avoid
+ * stomping concurrent edits), run planNniEdit, and PUT the result back.
+ * Streams progress. (Channel name kept as executeFloodChange for wire
+ * compatibility.)
  *
  * Concurrency is kept low (default 3) — OLT writes carry a much larger
  * blast radius than ONU reads, so we deliberately stay below the ONU
@@ -666,8 +668,7 @@ ipcMain.handle('api:executeFloodChange', async (event, opts) => {
   try {
     const c = requireClient();
     const {
-      oltIds, tagPattern, fromMode = 'private',
-      targetMode = 'auto', ponFloodIdValue = 0,
+      oltIds, tagPattern, flood = null, dhcpv4 = null, dhcpv6 = null,
       concurrency = 3,
     } = opts || {};
     const queue = [...oltIds];
@@ -683,9 +684,7 @@ ipcMain.handle('api:executeFloodChange', async (event, opts) => {
         try {
           const cfg = await c.getOltConfig(id);
           if (!cfg) throw new Error('OLT not found');
-          const plan = planFloodChange(cfg, {
-            tagPattern, fromMode, targetMode, ponFloodIdValue,
-          });
+          const plan = planNniEdit(cfg, { tagPattern, flood, dhcpv4, dhcpv6 });
           if (plan.changes.length === 0) {
             entry = { oltId: id, ok: true, noop: true, changes: [], skipped: plan.unchanged };
           } else {