fix(installer): stop mislabeling stdout-style progress as stderr

Both installers (Electron bootstrap-runner + Tauri) hardcoded a literal
`stderr: ` prefix onto every line that arrived on fd 2. Tools like
uv/pip/git/npm write normal progress to stderr by design, so routine
install output showed up tagged as "stderr" (and rendered red in the
Tauri progress UI), making a healthy install look like it was erroring.

Carry the stream as structured metadata (`stream: 'stdout' | 'stderr'`)
on the log event instead of mangling the line text. The UI now styles
stderr subtly (dimmed) rather than alarmingly, and the persistent
forensic logs keep their stdout/stderr distinction.

apps/desktop/electron/bootstrap-runner.cjs

@@ -22,7 +22,7 @@
  *   { type: 'manifest',  stages: [{name, title, category, needs_user_input}, ...] }
  *   { type: 'stage',     name, state: 'running'|'succeeded'|'skipped'|'failed',
  *                        json?, durationMs?, error? }
- *   { type: 'log',       stage?, line }      // raw line from install.ps1
+ *   { type: 'log',       stage?, line, stream: 'stdout'|'stderr' } // raw line from install.ps1
  *   { type: 'complete',  marker: <written marker payload> }
  *   { type: 'failed',    stage?, error }     // bootstrap aborted
  *
@@ -229,7 +229,7 @@ function spawnPowerShell(scriptPath, args, { emit, stageName, abortSignal, herme
       while ((nl = stdoutBuf.indexOf('\n')) !== -1) {
         const line = stdoutBuf.slice(0, nl).replace(/\r$/, '')
         stdoutBuf = stdoutBuf.slice(nl + 1)
-        if (line) emit && emit({ type: 'log', stage: stageName, line })
+        if (line) emit && emit({ type: 'log', stage: stageName, line, stream: 'stdout' })
       }
     })
 
@@ -241,7 +241,7 @@ function spawnPowerShell(scriptPath, args, { emit, stageName, abortSignal, herme
       while ((nl = stderrBuf.indexOf('\n')) !== -1) {
         const line = stderrBuf.slice(0, nl).replace(/\r$/, '')
         stderrBuf = stderrBuf.slice(nl + 1)
-        if (line) emit && emit({ type: 'log', stage: stageName, line: `stderr: ${line}` })
+        if (line) emit && emit({ type: 'log', stage: stageName, line, stream: 'stderr' })
       }
     })
 
@@ -253,8 +253,8 @@ function spawnPowerShell(scriptPath, args, { emit, stageName, abortSignal, herme
     child.on('close', (code, signal) => {
       if (abortSignal) abortSignal.removeEventListener('abort', onAbort)
       // Flush any trailing bytes
-      if (stdoutBuf) emit && emit({ type: 'log', stage: stageName, line: stdoutBuf })
-      if (stderrBuf) emit && emit({ type: 'log', stage: stageName, line: `stderr: ${stderrBuf}` })
+      if (stdoutBuf) emit && emit({ type: 'log', stage: stageName, line: stdoutBuf, stream: 'stdout' })
+      if (stderrBuf) emit && emit({ type: 'log', stage: stageName, line: stderrBuf, stream: 'stderr' })
       resolve({ stdout, stderr, code, signal, killed })
     })
   })
@@ -299,7 +299,7 @@ function spawnBash(scriptPath, args, { emit, stageName, abortSignal, hermesHome
       while ((nl = stdoutBuf.indexOf('\n')) !== -1) {
         const line = stdoutBuf.slice(0, nl).replace(/\r$/, '')
         stdoutBuf = stdoutBuf.slice(nl + 1)
-        if (line) emit && emit({ type: 'log', stage: stageName, line })
+        if (line) emit && emit({ type: 'log', stage: stageName, line, stream: 'stdout' })
       }
     })
 
@@ -311,7 +311,7 @@ function spawnBash(scriptPath, args, { emit, stageName, abortSignal, hermesHome
       while ((nl = stderrBuf.indexOf('\n')) !== -1) {
         const line = stderrBuf.slice(0, nl).replace(/\r$/, '')
         stderrBuf = stderrBuf.slice(nl + 1)
-        if (line) emit && emit({ type: 'log', stage: stageName, line: `stderr: ${line}` })
+        if (line) emit && emit({ type: 'log', stage: stageName, line, stream: 'stderr' })
       }
     })
 
@@ -322,8 +322,8 @@ function spawnBash(scriptPath, args, { emit, stageName, abortSignal, hermesHome
 
     child.on('close', (code, signal) => {
       if (abortSignal) abortSignal.removeEventListener('abort', onAbort)
-      if (stdoutBuf) emit && emit({ type: 'log', stage: stageName, line: stdoutBuf })
-      if (stderrBuf) emit && emit({ type: 'log', stage: stageName, line: `stderr: ${stderrBuf}` })
+      if (stdoutBuf) emit && emit({ type: 'log', stage: stageName, line: stdoutBuf, stream: 'stdout' })
+      if (stderrBuf) emit && emit({ type: 'log', stage: stageName, line: stderrBuf, stream: 'stderr' })
       resolve({ stdout, stderr, code, signal, killed })
     })
   })

apps/desktop/electron/main.cjs

@@ -722,7 +722,7 @@ function broadcastBootstrapEvent(ev) {
       error: ev.error ?? null
     }
   } else if (ev.type === 'log') {
-    bootstrapState.log.push({ ts: Date.now(), stage: ev.stage || null, line: ev.line })
+    bootstrapState.log.push({ ts: Date.now(), stage: ev.stage || null, line: ev.line, stream: ev.stream || 'stdout' })
     if (bootstrapState.log.length > BOOTSTRAP_LOG_RING_MAX) {
       bootstrapState.log.splice(0, bootstrapState.log.length - BOOTSTRAP_LOG_RING_MAX)
     }

apps/desktop/src/components/desktop-install-overlay.tsx

@@ -177,7 +177,7 @@ function applyEvent(state: DesktopBootstrapState, ev: DesktopBootstrapEvent): De
     }
   }
   if (ev.type === 'log') {
-    const next = state.log.concat({ ts: Date.now(), stage: ev.stage ?? null, line: ev.line })
+    const next = state.log.concat({ ts: Date.now(), stage: ev.stage ?? null, line: ev.line, stream: ev.stream })
     while (next.length > 500) next.shift()
     return { ...state, log: next }
   }
@@ -431,7 +431,10 @@ export function DesktopInstallOverlay({ enabled = true }: DesktopInstallOverlayP
                 ) : (
                   <>
                     {state.log.map((entry, i) => (
-                      <div key={i} className="whitespace-pre-wrap break-words">
+                      <div
+                        key={i}
+                        className={cn('whitespace-pre-wrap break-words', entry.stream === 'stderr' && 'text-muted-foreground')}
+                      >
                         {entry.stage ? <span className="text-muted-foreground/70">[{entry.stage}] </span> : null}
                         <span>{entry.line}</span>
                       </div>

apps/desktop/src/global.d.ts

@@ -222,7 +222,7 @@ export interface DesktopBootstrapState {
   manifest: { type: 'manifest'; stages: DesktopBootstrapStageDescriptor[]; protocolVersion: number | null } | null
   stages: Record<string, DesktopBootstrapStageResult>
   error: string | null
-  log: Array<{ ts: number; stage: string | null; line: string }>
+  log: Array<{ ts: number; stage: string | null; line: string; stream?: 'stdout' | 'stderr' }>
   startedAt: number | null
   completedAt: number | null
   unsupportedPlatform: DesktopBootstrapUnsupportedPlatform | null
@@ -238,7 +238,7 @@ export type DesktopBootstrapEvent =
       json?: DesktopBootstrapStageResult['json']
       error?: string | null
     }
-  | { type: 'log'; stage?: string | null; line: string }
+  | { type: 'log'; stage?: string | null; line: string; stream?: 'stdout' | 'stderr' }
   | { type: 'complete'; marker: Record<string, unknown> }
   | { type: 'failed'; stage?: string | null; error: string }
   | {