refactor(cli-run): stream reasoning text instead of summarized thinking line

Replace the single-line "Thinking: <summary>" rendering with direct streaming
of reasoning tokens via writePaddedText. Removes maybePrintThinkingLine and
renderThinkingLine in favor of incremental output with dim styling.

🤖 Generated with assistance of [OhMyOpenCode](https://github.com/code-yeongyu/oh-my-opencode)

src/cli/run/event-handlers.ts

@@ -20,7 +20,6 @@ import {
   closeThinkBlock,
   openThinkBlock,
   renderAgentHeader,
-  renderThinkingLine,
   writePaddedText,
 } from "./output-renderer"
 
@@ -111,10 +110,15 @@ export function handleMessagePartUpdated(ctx: RunContext, payload: EventPayload,
 
   if (part.type === "reasoning") {
     ensureThinkBlockOpen(state)
-    const reasoningText = part.text ?? state.lastReasoningText
-    maybePrintThinkingLine(state, reasoningText)
+    const reasoningText = part.text ?? ""
+    const newText = reasoningText.slice(state.lastReasoningText.length)
+    if (newText) {
+      const padded = writePaddedText(newText, state.thinkingAtLineStart)
+      process.stdout.write(pc.dim(padded.output))
+      state.thinkingAtLineStart = padded.atLineStart
+      state.hasReceivedMeaningfulWork = true
+    }
     state.lastReasoningText = reasoningText
-    state.hasReceivedMeaningfulWork = true
     return
   }
 
@@ -157,9 +161,10 @@ export function handleMessagePartDelta(ctx: RunContext, payload: EventPayload, s
 
   if (partType === "reasoning") {
     ensureThinkBlockOpen(state)
-    const nextReasoningText = `${state.lastReasoningText}${delta}`
-    maybePrintThinkingLine(state, nextReasoningText)
-    state.lastReasoningText = nextReasoningText
+    const padded = writePaddedText(delta, state.thinkingAtLineStart)
+    process.stdout.write(pc.dim(padded.output))
+    state.thinkingAtLineStart = padded.atLineStart
+    state.lastReasoningText += delta
     state.hasReceivedMeaningfulWork = true
     return
   }
@@ -226,6 +231,7 @@ export function handleMessageUpdated(ctx: RunContext, payload: EventPayload, sta
   state.hasPrintedThinkingLine = false
   state.lastThinkingSummary = ""
   state.textAtLineStart = true
+  state.thinkingAtLineStart = false
   closeThinkBlockIfNeeded(state)
 
   const agent = props?.info?.agent ?? null
@@ -298,6 +304,7 @@ function ensureThinkBlockOpen(state: EventState): void {
   openThinkBlock()
   state.inThinkBlock = true
   state.hasPrintedThinkingLine = false
+  state.thinkingAtLineStart = false
 }
 
 function closeThinkBlockIfNeeded(state: EventState): void {
@@ -306,19 +313,5 @@ function closeThinkBlockIfNeeded(state: EventState): void {
   state.inThinkBlock = false
   state.lastThinkingLineWidth = 0
   state.lastThinkingSummary = ""
-}
-
-function maybePrintThinkingLine(state: EventState, text: string): void {
-  const normalized = text.replace(/\s+/g, " ").trim()
-  if (!normalized) return
-
-  const summary = normalized
-  if (summary === state.lastThinkingSummary) return
-
-  state.lastThinkingLineWidth = renderThinkingLine(
-    summary,
-    state.lastThinkingLineWidth,
-  )
-  state.lastThinkingSummary = summary
-  state.hasPrintedThinkingLine = true
+  state.thinkingAtLineStart = false
 }

src/cli/run/event-state.ts

@@ -35,6 +35,8 @@ export interface EventState {
   lastThinkingSummary: string
   /** Whether text stream is currently at line start (for padding) */
   textAtLineStart: boolean
+  /** Whether reasoning stream is currently at line start (for padding) */
+  thinkingAtLineStart: boolean
 }
 
 export function createEventState(): EventState {
@@ -60,5 +62,6 @@ export function createEventState(): EventState {
     messageRoleById: {},
     lastThinkingSummary: "",
     textAtLineStart: true,
+    thinkingAtLineStart: false,
   }
 }

src/cli/run/message-part-delta.test.ts

@@ -215,8 +215,7 @@ describe("message.part.delta handling", () => {
 
     //#then
     const rendered = stdoutSpy.mock.calls.map((call) => String(call[0] ?? "")).join("")
-    expect(rendered).toContain("\r")
-    expect(rendered).toContain("Thinking: Composing final summary")
+    expect(rendered).toContain("┃  Thinking: Composing final summary")
     expect(rendered).toContain("in Korean with specifics.")
 
     if (previous !== undefined) process.env.GITHUB_ACTIONS = previous
@@ -282,7 +281,7 @@ describe("message.part.delta handling", () => {
     //#then
     const rendered = stdoutSpy.mock.calls.map((call) => String(call[0] ?? "")).join("")
     const renderCount = rendered.split("Thinking:").length - 1
-    expect(renderCount).toBe(2)
+    expect(renderCount).toBe(1)
 
     if (previous !== undefined) process.env.GITHUB_ACTIONS = previous
     stdoutSpy.mockRestore()

src/cli/run/output-renderer.ts

@@ -25,29 +25,11 @@ export function renderAgentHeader(
 }
 
 export function openThinkBlock(): void {
-  return
+  process.stdout.write("\n  ┃  Thinking: ")
 }
 
 export function closeThinkBlock(): void {
-  process.stdout.write("\n")
-}
-
-export function renderThinkingLine(
-  summary: string,
-  previousWidth: number,
-): number {
-  const line = `  ┃  Thinking: ${summary}  `
-  const isGitHubActions = process.env.GITHUB_ACTIONS === "true"
-
-  if (isGitHubActions) {
-    process.stdout.write(`${pc.dim(line)}\n`)
-    return line.length
-  }
-
-  const minPadding = 6
-  const clearPadding = Math.max(previousWidth - line.length + minPadding, minPadding)
-  process.stdout.write(`\r${pc.dim(line)}${" ".repeat(clearPadding)}`)
-  return line.length
+  process.stdout.write("  \n")
 }
 
 export function writePaddedText(