Add bulk OLT PON flooding-mode tool; restore README; docs

Adds a second bulk workflow alongside the firmware upgrader: changing
PON flooding mode (private<->auto) on OLT NNI services across many OLTs.

Flooding mode is encoded by the presence of the "PON FLOOD ID" key on
each OLT-CFG["NNI Networks"] entry (present = private, absent = auto).
private->auto deletes the key; auto->private sets it to 0. The rest of
the OLT-CFG is preserved (PUT-as-replace, same as ONU-CFG).

- src/mcms-api.js: listAllOltConfigs / getOltConfig / putOltConfig, plus
  pure helpers floodModeOfNni, summarizeOltNniNetworks, planFloodChange
  (planFloodChange clones and never mutates its input)
- main.js: api:listOlts + api:executeFloodChange IPC handlers
  (concurrency 3, GET->plan->PUT, streams olt-flood:progress)
- preload.js: expose both channels + onFloodProgress
- renderer: OLT inspector view (#view-olts), two-step APPLY confirm,
  auto-saved pon-olt-flood-*.csv result report
- Restore README.md (lost to a filesystem error) and document the new
  feature in README.md and CLAUDE.md (new section 14)

Verified: npm run check passes; pure helpers unit-tested for the
no-mutation, idempotency, and rollback invariants.

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

renderer/index.html

@@ -100,6 +100,10 @@
       <h2>After-upgrade verification</h2>
       <p class="muted small">Open a saved <code>pon-upgrade-*.csv</code> to compare the recorded FEC + optical readings against the current state of those ONUs.</p>
       <button id="btn-to-verify" class="ghost">Verify previous upgrade…</button>
+
+      <h2>OLT flooding mode</h2>
+      <p class="muted small">Bulk-check or fix PON flooding mode on OLT NNI services. Default rule: match <code>s0.c76.c0</code> with mode <code>private</code> and switch to <code>auto</code>.</p>
+      <button id="btn-to-olts" class="ghost">Open OLT inspector…</button>
     </div>
 
     <div class="panel-main">
@@ -246,6 +250,75 @@
     </div>
   </section>
 
+  <!-- ================= OLT inspector view ================= -->
+  <section id="view-olts" class="view hidden">
+    <div class="panel-left">
+      <h2>Filters</h2>
+      <label>NNI TAG MATCH pattern
+        <input id="olt-tag-pattern" type="text" value="s0.c76.c0" placeholder="e.g. s0.c76.c0 or s0.c76.*" />
+      </label>
+      <label>Current mode
+        <select id="olt-mode-filter">
+          <option value="private" selected>Private (PON FLOOD ID set)</option>
+          <option value="auto">Auto (no PON FLOOD ID)</option>
+          <option value="any">Any</option>
+        </select>
+      </label>
+      <label>OLT name contains
+        <input id="olt-name-filter" type="search" placeholder="e.g. OLT5" />
+      </label>
+      <button id="btn-load-olts" class="primary">Load OLTs</button>
+      <p class="muted small" id="olt-status"></p>
+
+      <h2>Selection</h2>
+      <div class="selected-summary">
+        <div><strong id="olt-sel-count">0</strong> OLT(s) selected · <strong id="olt-svc-count">0</strong> service slot(s) will change</div>
+        <div class="row">
+          <button id="btn-olt-select-all">Select all matching</button>
+          <button id="btn-olt-select-none" class="ghost">Clear</button>
+        </div>
+      </div>
+
+      <h2>Action</h2>
+      <label>Change matching services
+        <select id="olt-action">
+          <option value="private2auto" selected>Private → Auto (remove PON FLOOD ID)</option>
+          <option value="auto2private">Auto → Private (set PON FLOOD ID = 0)</option>
+        </select>
+      </label>
+
+      <div class="row">
+        <button id="btn-olts-back" class="ghost">← Back to fleet</button>
+        <button id="btn-olt-execute" class="danger" disabled>Execute change…</button>
+      </div>
+      <p id="olt-exec-status" class="small muted"></p>
+    </div>
+
+    <div class="panel-main">
+      <div class="fleet-head">
+        <h2>OLTs (<span id="olt-count">0</span> shown, <span id="olt-total">0</span> total)</h2>
+        <div class="row small muted">
+          <span>Each row shows the matching NNI services. Selecting an OLT queues every matching service on it for change.</span>
+        </div>
+      </div>
+      <div class="fleet-table-wrap">
+        <table class="fleet-table" id="olt-table">
+          <thead>
+            <tr>
+              <th><input type="checkbox" id="olt-th-check" /></th>
+              <th>OLT MAC</th>
+              <th>Name</th>
+              <th>PON mode</th>
+              <th>FW</th>
+              <th>Matching NNI services</th>
+            </tr>
+          </thead>
+          <tbody id="olt-tbody"></tbody>
+        </table>
+      </div>
+    </div>
+  </section>
+
   <script src="app.js"></script>
 </body>
 </html>