Add Portainer-style container name replace on deploy.

When deploying a container whose name already exists, prompt to Replace
(stop and remove the old container) or Cancel. Server accepts replace:true
to perform the swap; clients pre-check names and retry on conflict races.

ui/ops-app.js

@@ -344,9 +344,12 @@ export function isJobDrawerActive() {
 export async function deployContainerWithSteps(args) {
   /** @type {{ pulledOk: boolean }} */
   const state = { pulledOk: false }
+  const replace = args.replace === true
 
   return runJob(
-    `Deploy ${args.containerName || 'container'}`,
+    replace
+      ? `Replace ${args.containerName || 'container'}`
+      : `Deploy ${args.containerName || 'container'}`,
     [
       {
         id: 'validate',
@@ -359,6 +362,7 @@ export async function deployContainerWithSteps(args) {
           }
           log(`Name=${args.containerName}`)
           log(`Image=${args.image}`)
+          if (replace) log('Mode: replace existing container with same name')
           if (args.ports?.length) log(`Ports: ${args.ports.join(', ')}`)
           if (args.volumes?.length) log(`Volumes: ${args.volumes.join(', ')}`)
           if (args.networkMode) log(`Network mode: ${args.networkMode}`)
@@ -391,18 +395,37 @@ export async function deployContainerWithSteps(args) {
       },
       {
         id: 'create',
-        label: 'Create & start container',
+        label: replace ? 'Replace, create & start' : 'Create & start container',
         run: async ({ log }) => {
-          log('Creating and starting container…')
+          log(
+            replace
+              ? 'Removing previous container (if present), then creating…'
+              : 'Creating and starting container…'
+          )
           // Only skip server pull when client pull already succeeded
-          const payload = { ...args, skipPull: state.pulledOk === true }
+          const payload = {
+            ...args,
+            skipPull: state.pulledOk === true,
+            replace: replace === true,
+          }
           try {
             const res = await manager.request(Methods.deployContainer, payload)
             log(res?.message || `Container "${args.containerName}" is running`)
             if (res?.id) log(`ID: ${String(res.id).slice(0, 12)}`)
+            if (replace) log('Previous container was replaced')
             return res
           } catch (err) {
             const info = explainError(err, 'deployContainer')
+            // Keep conflict code so outer deploy can offer Replace
+            if (
+              err?.code === 'CONTAINER_NAME_CONFLICT' ||
+              info.code === 'CONTAINER_NAME_CONFLICT'
+            ) {
+              const e = new Error(err.message || info.message)
+              e.code = 'CONTAINER_NAME_CONFLICT'
+              e.cause = err
+              throw e
+            }
             // Re-throw with full descriptive text for the job log formatter
             const full = [info.title, info.message, info.recovery ? `How to fix: ${info.recovery}` : '']
               .filter(Boolean)