feat(election): production-ready audit log with server-side filter + pagination

- Add m_election_audit_log table via Liquibase (0341)
- ElectionAuditLog entity, ElectionAuditAction enum (21 actions)
- ElectionAuditService: log() with double try-catch, getAuditLogPaged()
  with entityType/action/full-text filters, size cap at 100, page safety
- ElectionAuditLogRepository: findWithFilters() JPQL with optional params
- All 4 election API resources wired with audit calls (create/update/
  activate/nominations/voting/candidates/votes/results)
- GET /{electionId}/audit-log accepts ?entityType=&action=&search=&page=&size=

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

fineract-provider/src/main/resources/db/changelog/tenant/changelog-tenant.xml

@@ -368,4 +368,5 @@
     <include file="parts/0338_election_ceo_precheck_extended_checks.xml" relativeToChangelogFile="true"/>
     <include file="parts/0339_election_ceo_precheck_family_loan_check.xml" relativeToChangelogFile="true"/>
     <include file="parts/0340_election_candidate_symbol_text.xml" relativeToChangelogFile="true"/>
+    <include file="parts/0341_election_audit_log.xml" relativeToChangelogFile="true"/>
 </databaseChangeLog>

fineract-provider/src/main/resources/db/changelog/tenant/parts/0340_election_candidate_symbol_text.xml

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<databaseChangeLog xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
+                   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+                   xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
+                   http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-4.1.xsd">
+
+    <changeSet id="0340-election-candidate-symbol-text" author="fineract">
+        <preConditions onFail="MARK_RAN">
+            <columnExists tableName="m_election_candidate" columnName="symbol"/>
+        </preConditions>
+        <modifyDataType tableName="m_election_candidate" columnName="symbol" newDataType="TEXT"/>
+        <comment>Expand symbol column to TEXT to support base64 image data URLs</comment>
+    </changeSet>
+
+</databaseChangeLog>

fineract-provider/src/main/resources/db/changelog/tenant/parts/0341_election_audit_log.xml

@@ -0,0 +1,48 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<databaseChangeLog xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
+        http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-4.1.xsd">
+
+    <changeSet id="0341-election-audit-log" author="CBS">
+        <preConditions onFail="MARK_RAN">
+            <not><tableExists tableName="m_election_audit_log"/></not>
+        </preConditions>
+
+        <createTable tableName="m_election_audit_log">
+            <column name="id" type="BIGSERIAL" autoIncrement="true">
+                <constraints primaryKey="true" nullable="false"/>
+            </column>
+            <column name="election_id" type="BIGINT"/>
+            <column name="entity_type" type="VARCHAR(50)">
+                <constraints nullable="false"/>
+            </column>
+            <column name="entity_id" type="BIGINT"/>
+            <column name="action" type="VARCHAR(100)">
+                <constraints nullable="false"/>
+            </column>
+            <column name="performed_by_id" type="BIGINT"/>
+            <column name="performed_by_name" type="VARCHAR(100)"/>
+            <column name="office_id" type="BIGINT"/>
+            <column name="ip_address" type="VARCHAR(50)"/>
+            <column name="details" type="TEXT"/>
+            <column name="description" type="VARCHAR(500)"/>
+            <column name="created_at" type="TIMESTAMP" defaultValueComputed="NOW()">
+                <constraints nullable="false"/>
+            </column>
+        </createTable>
+
+        <createIndex indexName="idx_election_audit_election_created"
+                     tableName="m_election_audit_log">
+            <column name="election_id"/>
+            <column name="created_at" descending="true"/>
+        </createIndex>
+
+        <createIndex indexName="idx_election_audit_entity"
+                     tableName="m_election_audit_log">
+            <column name="entity_type"/>
+            <column name="entity_id"/>
+        </createIndex>
+    </changeSet>
+
+</databaseChangeLog>