fix: match original table UI with immediate per-action submission

Replace the Save All workflow with the original per-action behavior:
- Edit row: shows Save/Cancel buttons, submits full set immediately
- Delete row: shows confirmation dialog, submits full set immediately
- Add row: submits full set immediately on Add click

Moves Alpine.js logic into a proper envVarEditor component in
app-detail.js. Initializes env var data from hidden span elements
with data attributes for safe HTML escaping.

All actions collect the complete env var set and POST to the single
bulk endpoint POST /apps/{id}/env — no Save All button needed.

static/js/app-detail.js

@@ -6,6 +6,68 @@
  */
 
 document.addEventListener("alpine:init", () => {
+    // ============================================
+    // Environment Variable Editor Component
+    // ============================================
+    Alpine.data("envVarEditor", () => ({
+        vars: [],
+        editIdx: -1,
+        editKey: "",
+        editVal: "",
+
+        init() {
+            this.vars = Array.from(this.$el.querySelectorAll(".env-init")).map(
+                (span) => ({
+                    key: span.dataset.key,
+                    value: span.dataset.value,
+                }),
+            );
+        },
+
+        startEdit(i) {
+            this.editIdx = i;
+            this.editKey = this.vars[i].key;
+            this.editVal = this.vars[i].value;
+        },
+
+        saveEdit(i) {
+            this.vars[i] = { key: this.editKey, value: this.editVal };
+            this.editIdx = -1;
+            this.submitAll();
+        },
+
+        removeVar(i) {
+            if (!window.confirm("Delete this environment variable?")) {
+                return;
+            }
+
+            this.vars.splice(i, 1);
+            this.submitAll();
+        },
+
+        addVar(keyEl, valEl) {
+            const k = keyEl.value.trim();
+            const v = valEl.value.trim();
+
+            if (!k) {
+                return;
+            }
+
+            this.vars.push({ key: k, value: v });
+            this.submitAll();
+        },
+
+        submitAll() {
+            this.$refs.bulkData.value = this.vars
+                .map((e) => e.key + "=" + e.value)
+                .join("\n");
+            this.$refs.bulkForm.submit();
+        },
+    }));
+
+    // ============================================
+    // App Detail Page Component
+    // ============================================
     Alpine.data("appDetail", (config) => ({
         appId: config.appId,
         currentDeploymentId: config.initialDeploymentId,