fix(pilot): Phase 9 review — partial-outcome notes + per-fix script-builder remount

Addresses docs/FlowAssist_Migration/Issues/phase-9-review-issues.md.

Issue #1 (High): "Applied partially" from the escalation intercept silently
dropped because the backend requires notes on applied_partial and the dialog
sent none. The catch was silent and the UI advanced into the conclude flow
as if the outcome were recorded.
- EscalateInterceptDialog now has a two-step flow: clicking the partial
  choice reveals a notes textarea (autofocused, required non-empty) plus
  Back / "Record partial & escalate" buttons.
- onChoose signature extended to (choice, notes?).
- handleInterceptChoice passes notes to patchOutcome; on failure it
  surfaces a toast and does NOT advance to the conclude modal, so the
  intercept stays open for retry.

Issue #2 (Medium/High): ScriptBuilderTab kept local state across active-fix
changes within the same pilot session, so a stale draft could PATCH against
a newer fix.id. Added key={activeFix.id} on the mount — forces a clean
remount per fix; backend get-or-create (keyed on user+ai_session_id) still
returns the same session row, which is the intended resume-on-refresh
semantic; but messages/editorBuffer/latestScript local state resets.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/src/components/pilot/EscalateInterceptDialog.tsx

@@ -8,14 +8,16 @@
  * Visual reference: docs/FlowAssist_Migration/mockups/07-verify-states.html
  * (panel C).
  */
+import { useState } from 'react'
 import { X, AlertCircle, Check, Info } from 'lucide-react'
+import { cn } from '@/lib/utils'
 import type { FixOutcome } from '@/api/sessionSuggestedFixes'
 
 export type InterceptChoice = FixOutcome | 'never_applied'
 
 export interface EscalateInterceptDialogProps {
   fixTitle: string
-  onChoose: (choice: InterceptChoice) => void
+  onChoose: (choice: InterceptChoice, notes?: string) => void
   onClose: () => void
 }
 
@@ -24,6 +26,11 @@ export function EscalateInterceptDialog({
   onChoose,
   onClose,
 }: EscalateInterceptDialogProps) {
+  const [partialStep, setPartialStep] = useState(false)
+  const [partialNotes, setPartialNotes] = useState('')
+
+  const notesValid = partialNotes.trim().length > 0
+
   return (
     <>
       <div
@@ -36,6 +43,8 @@ export function EscalateInterceptDialog({
         aria-label="Capture fix outcome before escalating"
         className="absolute bottom-full mb-2 left-0 z-50 w-[340px] rounded-lg border border-white/15 bg-card p-3.5 shadow-[0_18px_40px_rgba(0,0,0,0.55)]"
       >
+        {!partialStep ? (
+          <>
             <div className="font-heading font-semibold text-[13px] text-heading mb-1">
               Before escalating — what happened with the fix?
             </div>
@@ -54,7 +63,7 @@ export function EscalateInterceptDialog({
                 <span className="text-[10.5px] text-muted-foreground font-mono px-1.5 py-[2px] rounded bg-white/[0.05]">↵</span>
               </button>
               <button
-            onClick={() => onChoose('applied_partial')}
+                onClick={() => setPartialStep(true)}
                 className="flex items-center gap-2.5 px-3 py-2.5 rounded-lg border border-white/10 bg-elevated text-[12.5px] text-primary hover:bg-sidebar transition-colors text-left"
               >
                 <Info size={13} strokeWidth={2} />
@@ -75,6 +84,45 @@ export function EscalateInterceptDialog({
                 <span className="flex-1">Never actually applied it</span>
               </button>
             </div>
+          </>
+        ) : (
+          <>
+            <div className="font-heading font-semibold text-[13px] text-heading mb-1">
+              What partially worked?
+            </div>
+            <div className="text-[12px] text-muted-foreground leading-[1.5] mb-3">
+              A short note for whoever picks this up — what you tried, what worked, what&apos;s still broken.
+            </div>
+            <textarea
+              autoFocus
+              value={partialNotes}
+              onChange={(e) => setPartialNotes(e.target.value)}
+              placeholder="e.g. Cleared cached creds; rebuild profile still hung on sync."
+              className="w-full h-24 resize-none rounded-md border border-white/10 bg-elevated px-2.5 py-2 text-[12.5px] text-primary placeholder:text-muted-foreground focus:outline-none focus:border-accent"
+            />
+            <div className="flex items-center justify-between gap-2 mt-3">
+              <button
+                onClick={() => {
+                  setPartialStep(false)
+                  setPartialNotes('')
+                }}
+                className="text-[12px] text-muted-foreground hover:text-primary transition-colors"
+              >
+                ← Back
+              </button>
+              <button
+                onClick={() => onChoose('applied_partial', partialNotes.trim())}
+                disabled={!notesValid}
+                className={cn(
+                  'px-3 py-1.5 rounded text-[12.5px] font-semibold transition-colors',
+                  'bg-accent text-[#0a0d14] hover:brightness-110 disabled:opacity-50 disabled:cursor-not-allowed',
+                )}
+              >
+                Record partial &amp; escalate
+              </button>
+            </div>
+          </>
+        )}
       </div>
     </>
   )

frontend/src/pages/AssistantChatPage.tsx

@@ -656,19 +656,33 @@ export default function AssistantChatPage() {
     setShowConclude(true)
   }, [activeFix])
 
-  const handleInterceptChoice = useCallback(async (choice: InterceptChoice) => {
+  const handleInterceptChoice = useCallback(async (choice: InterceptChoice, notes?: string) => {
     const stored = escalateIntercept
+    if (!stored || !activeChatId) {
       setEscalateIntercept(null)
-    if (!stored || !activeChatId) return
+      return
+    }
     const outcomeToSend: FixOutcome =
       choice === 'never_applied' ? 'dismissed' : choice
     try {
       const updated = await sessionSuggestedFixesApi.patchOutcome(
-        activeChatId, stored.fixId, outcomeToSend,
+        activeChatId, stored.fixId, outcomeToSend, notes,
       )
       setActiveFix(updated)
-    } catch { /* non-fatal — engineer can still escalate */ }
+      setEscalateIntercept(null)
       setShowConclude(true)
+    } catch (err) {
+      // applied_partial without notes (or any other 4xx) must surface — the
+      // previous silent catch let engineers believe the partial outcome was
+      // recorded while it was rejected server-side.
+      const message = choice === 'applied_partial'
+        ? 'Couldn’t record the partial outcome. Add a short note and try again.'
+        : 'Couldn’t record the outcome before escalating. Try again.'
+      toast.error(message)
+      // Keep the intercept open so the engineer can retry (partial path can
+      // re-enter the notes step from the dialog).
+      if (import.meta.env.DEV) console.warn('[AssistantChat] intercept outcome failed:', err)
+    }
   }, [activeChatId, escalateIntercept])
 
   // Phase 8: Resolve click — auto-mark applied_success if in verifying state
@@ -1629,7 +1643,12 @@ export default function AssistantChatPage() {
                 so both scroll positions and state are preserved across tab switches. */}
             {showTabStrip && activeFix && activeChatId && (
               <div className={cn('flex-1 min-h-0 flex flex-col', chatTab !== 'script_builder' && 'hidden')}>
+                {/* key={activeFix.id} forces a fresh mount when the active
+                    fix changes within the same pilot session — otherwise
+                    stale messages / editorBuffer / latestScript from the
+                    prior fix could submit against the new fix.id. */}
                 <ScriptBuilderTab
+                  key={activeFix.id}
                   fix={activeFix}
                   pilotSessionId={activeChatId}
                   onProgressChange={setScriptBuilderHasProgress}