refactor(mobile): name the init option initialData, as the message does

The init option `data` becomes `initialData`, the message field's name,
so the controller passes it through unrenamed. The `preserveScroll` why
stays on the message type only, and the document test's title names the
three grids that carry the frame.

Claude-Session: https://claude.ai/code/session_01JNnE9qzUZMMnqpZWCqM3nb

config/scripts/mobile-web-app-terminal-probe-route.mjs

@@ -73,8 +73,8 @@ export default function TerminalProbeRoute() {
     globalThis.__orcaTerminalEngineErrors = globalThis.__orcaTerminalEngineErrors ?? []
     globalThis.__orcaTerminalBeforeInput = []
     globalThis.__orcaTerminalProbe = {
-      init: (cols, rows, data) =>
-        handleRef.current?.init({ cols, rows, data, oscLinks: [], frame: frameRef.current }),
+      init: (cols, rows, initialData) =>
+        handleRef.current?.init({ cols, rows, initialData, oscLinks: [], frame: frameRef.current }),
       write: (data) => handleRef.current?.write(data),
       selectAll: () => handleRef.current?.doSelectAll(),
       fit: () => handleRef.current?.fitDimensions(frameRef.current),

mobile/src/session/mobile-session-route-parity.test.ts

@@ -136,7 +136,8 @@ const HEAD_CALLBACK_IDENTITY_SHA256 =
 // Again when the document took the hold rule and the subscribe stopped holding its grid.
 // Again when an init took one options object.
 // Again when the frame's layout became one `notifyTerminalFrame`.
-const HEAD_CALLBACK_BODY_SHA256 = '8f2ecfc86d6b50dfcf2248135c12a1a97c0b63a50176fc330781e805f388bbd3'
+// Again when the init option took the message's name, `initialData`.
+const HEAD_CALLBACK_BODY_SHA256 = '4848e925f478f1656f26031c1bdebbb9f2da60811c7e91cfd732fc9da9764079'
 // Refreshed for the startup effect: both `worktree.activate` sends became `worktreeActivate`, and
 // the sleeping-agent check reads that operation's verdict instead of the reply envelope. Refreshed
 // again when the reporter took the reply and interpreted it itself, retiring the hand-built

mobile/src/session/use-mobile-session-terminal-subscription.ts

@@ -195,7 +195,7 @@ export function useMobileSessionTerminalSubscription(
               })
               return
             }
-            ref.init({ cols, rows, data: initialData, oscLinks, frame: terminalFrameRef.current })
+            ref.init({ cols, rows, initialData, oscLinks, frame: terminalFrameRef.current })
             initializedHandlesRef.current.add(handle)
             if (data.displayMode) {
               const displayMode = data.displayMode as MobileDisplayMode
@@ -266,7 +266,7 @@ export function useMobileSessionTerminalSubscription(
               getTerminalRef(handle)?.init({
                 cols,
                 rows,
-                data: serialized,
+                initialData: serialized,
                 preserveScroll: true,
                 oscLinks,
                 frame: terminalFrameRef.current

mobile/src/terminal/document/laid-out-cell-box.test.ts

@@ -128,7 +128,7 @@ describe('a started document', () => {
   const reflowTo = (scope: TerminalDocumentScope, cols: number) =>
     handleMsg(scope, { type: 'reflow', cols, rows: 47 })
 
-  it('takes the frame the app laid out from init, as from a measure', () => {
+  it('takes the frame the app laid out from init, resize and reflow', () => {
     const { scope } = started()
     try {
       handleMsg(scope, {

mobile/src/terminal/terminal-webview-cell-box.test.ts

@@ -125,7 +125,7 @@ describe('the cell box xterm laid out', () => {
     expect(handle().fitDimensions({ width: 427.5, height: 0 })).toBeNull()
     expect(handle().fitDimensions({ width: 427.5, height: 710 })).toEqual({ cols: 55, rows: 47 })
     const frame = { width: 427.5, height: 710 }
-    handle().init({ cols: 55, rows: 47, data: '', frame })
+    handle().init({ cols: 55, rows: 47, initialData: '', frame })
     handle().resize(55, 47, frame)
     handle().reflow(55, 47, frame)
     const grids = nativeWebViewMethods.postMessage.mock.calls
@@ -137,7 +137,7 @@ describe('the cell box xterm laid out', () => {
 
   it('sends nothing before a ready: a load start drops what was queued', () => {
     const { handle, notify, webView } = mount()
-    handle().init({ cols: 55, rows: 47, data: 'snapshot', frame: null })
+    handle().init({ cols: 55, rows: 47, initialData: 'snapshot', frame: null })
     expect(postedTypes()).toEqual([])
     act(() => webView().props.onLoadStart())
     notify({ type: 'web-ready', cellBox: cellAt(scale) })

mobile/src/terminal/terminal-webview-contract.ts

@@ -99,8 +99,7 @@ export type TerminalWebViewProps = {
 export type TerminalInit = {
   cols: number
   rows: number
-  data?: string
-  // Why: a width reflow re-streams the same content rewrapped; keep the reader's place.
+  initialData?: string
   preserveScroll?: boolean
   oscLinks?: TerminalOscLinkRange[]
   frame: TerminalFrame | null

mobile/src/terminal/terminal-write-coalescer-boundaries.test.ts

@@ -125,7 +125,7 @@ describe('terminal write coalescer boundaries', () => {
   it('clears the coalescer before posting init and clear (snapshot supersession)', () => {
     // Anchor on the init() signature (unique) — 'init(' alone also matches comments.
     const initStart = controllerSource.indexOf(
-      'init({ cols, rows, data, preserveScroll, oscLinks, frame }'
+      'init({ cols, rows, initialData, preserveScroll, oscLinks, frame }'
     )
     const initClear = controllerSource.indexOf('writeCoalescer.clear()', initStart)
     const initPost = controllerSource.indexOf("type: 'init'", initStart)

mobile/src/terminal/use-terminal-webview-controller.ts

@@ -263,7 +263,7 @@ export function useTerminalWebViewController(
       write(data: string) {
         writeCoalescer.write(data)
       },
-      init({ cols, rows, data, preserveScroll, oscLinks, frame }: TerminalInit) {
+      init({ cols, rows, initialData, preserveScroll, oscLinks, frame }: TerminalInit) {
         // Why: arm a fresh ready promise BEFORE posting init. The document resolves it via the
         // 'ready' notify at the end of its rAF chain.
         promises.armReady()
@@ -274,7 +274,7 @@ export function useTerminalWebViewController(
           type: 'init',
           cols,
           rows,
-          initialData: data,
+          initialData,
           oscLinks,
           terminalTheme,
           fontScale: textScale,