feat(migration): implement interactive mapping resolution workflow

- Add SQLite database integration for environments and mappings
- Update TaskManager to support pausing tasks (AWAITING_MAPPING)
- Modify MigrationPlugin to detect missing mappings and wait for resolution
- Add frontend UI for handling missing mappings interactively
- Create dedicated migration routes and API endpoints
- Update .gitignore and project documentation

frontend/src/components/TaskRunner.svelte

@@ -15,6 +15,7 @@
     import { selectedTask, taskLogs } from '../lib/stores.js';
     import { getWsUrl } from '../lib/api.js';
     import { addToast } from '../lib/toasts.js';
+    import MissingMappingModal from './MissingMappingModal.svelte';
     // [/SECTION]
 
     let ws;
@@ -25,7 +26,10 @@
     let reconnectTimeout;
     let waitingForData = false;
     let dataTimeout;
-    let connectionStatus = 'disconnected'; // 'connecting', 'connected', 'disconnected', 'waiting', 'completed'
+    let connectionStatus = 'disconnected'; // 'connecting', 'connected', 'disconnected', 'waiting', 'completed', 'awaiting_mapping'
+    let showMappingModal = false;
+    let missingDbInfo = { name: '', uuid: '' };
+    let targetDatabases = [];
 
     // [DEF:connect:Function]
     /**
@@ -58,6 +62,17 @@
                 connectionStatus = 'completed';
                 ws.close();
             }
+
+            // Check for missing mapping signal
+            if (logEntry.message && logEntry.message.includes('Missing mapping for database UUID')) {
+                const uuidMatch = logEntry.message.match(/UUID: ([\w-]+)/);
+                if (uuidMatch) {
+                    missingDbInfo = { name: 'Unknown', uuid: uuidMatch[1] };
+                    connectionStatus = 'awaiting_mapping';
+                    fetchTargetDatabases();
+                    showMappingModal = true;
+                }
+            }
         };
 
         ws.onerror = (error) => {
@@ -85,6 +100,65 @@
     }
     // [/DEF:connect]
 
+    async function fetchTargetDatabases() {
+        const task = get(selectedTask);
+        if (!task || !task.params.to_env) return;
+        
+        try {
+            // We need to find the environment ID by name first
+            const envsRes = await fetch('/api/environments');
+            const envs = await envsRes.json();
+            const targetEnv = envs.find(e => e.name === task.params.to_env);
+            
+            if (targetEnv) {
+                const res = await fetch(`/api/environments/${targetEnv.id}/databases`);
+                targetDatabases = await res.json();
+            }
+        } catch (e) {
+            console.error('Failed to fetch target databases', e);
+        }
+    }
+
+    async function handleMappingResolve(event) {
+        const task = get(selectedTask);
+        const { sourceDbUuid, targetDbUuid, targetDbName } = event.detail;
+        
+        try {
+            // 1. Save mapping to backend
+            const envsRes = await fetch('/api/environments');
+            const envs = await envsRes.json();
+            const srcEnv = envs.find(e => e.name === task.params.from_env);
+            const tgtEnv = envs.find(e => e.name === task.params.to_env);
+
+            await fetch('/api/mappings', {
+                method: 'POST',
+                headers: { 'Content-Type': 'application/json' },
+                body: JSON.stringify({
+                    source_env_id: srcEnv.id,
+                    target_env_id: tgtEnv.id,
+                    source_db_uuid: sourceDbUuid,
+                    target_db_uuid: targetDbUuid,
+                    source_db_name: missingDbInfo.name,
+                    target_db_name: targetDbName
+                })
+            });
+
+            // 2. Resolve task
+            await fetch(`/api/tasks/${task.id}/resolve`, {
+                method: 'POST',
+                headers: { 'Content-Type': 'application/json' },
+                body: JSON.stringify({
+                    resolution_params: { resolved_mapping: { [sourceDbUuid]: targetDbUuid } }
+                })
+            });
+
+            connectionStatus = 'connected';
+            addToast('Mapping resolved, migration continuing...', 'success');
+        } catch (e) {
+            addToast('Failed to resolve mapping: ' + e.message, 'error');
+        }
+    }
+
     function startDataTimeout() {
         waitingForData = false;
         dataTimeout = setTimeout(() => {
@@ -151,6 +225,9 @@
                 {:else if connectionStatus === 'completed'}
                     <span class="h-3 w-3 rounded-full bg-blue-500"></span>
                     <span class="text-xs text-gray-500">Completed</span>
+                {:else if connectionStatus === 'awaiting_mapping'}
+                    <span class="h-3 w-3 rounded-full bg-orange-500 animate-pulse"></span>
+                    <span class="text-xs text-gray-500">Awaiting Mapping</span>
                 {:else}
                     <span class="h-3 w-3 rounded-full bg-red-500"></span>
                     <span class="text-xs text-gray-500">Disconnected</span>
@@ -177,6 +254,15 @@
         <p>No task selected.</p>
     {/if}
 </div>
+
+<MissingMappingModal
+    bind:show={showMappingModal}
+    sourceDbName={missingDbInfo.name}
+    sourceDbUuid={missingDbInfo.uuid}
+    {targetDatabases}
+    on:resolve={handleMappingResolve}
+    on:cancel={() => { connectionStatus = 'disconnected'; ws.close(); }}
+/>
 <!-- [/SECTION] -->
 
 <!-- [/DEF:TaskRunner] -->