feat: persist candidate fit and focus plan, stop re-running on every open

Extends the interview-prep persistence pattern (previous commit) to
the other two AI-generated per-job outputs that were re-running their
full AI call chain on every tab open: candidate-fit (4 AI calls) and
focus-plan (4 AI calls). Across all three tabs that's 9 AI calls fired
every single time a user revisits a job's AI workspace tabs.

Generalized into AiWorkspaceNote (OwnerUserId, JobApplicationId,
NoteType, ResultJson) rather than duplicating InterviewPrepNote's
per-field-column shape: CandidateFitDto and FocusPlanDto are irregular
and nested (up to 13 fields including a nested guidance object),
where per-field columns would be unreasonable. One table, keyed by
note type, serving both.

Same rules as interview prep: reuse across calls, regenerate when the
attachment selection changes, regenerate on explicit refresh. Frontend
gets the same "Regenerate" button on both tabs.

3 new tests (persist+reuse for both, refresh for candidate-fit).
Verified against the real dev DB.

job-tracker-ui/src/components/JobDetailsDialog.tsx

@@ -289,6 +289,18 @@ export default function JobDetailsDialog({ open, jobId, onClose, initialTab = 0,
     }).catch(() => setCandidateFit(null)).finally(() => setLoadingCandidateFit(false));
   }, [open, jobId, tab, candidateFit, selectedAttachmentCsv, candidateFitCache]);
 
+  // Persisted server-side like interview prep (career-workspace-implementation-roadmap.md Phase
+  // F5); Regenerate is the explicit escape hatch when the job has changed since it was written.
+  const regenerateCandidateFit = useCallback(() => {
+    if (!jobId) return;
+    setLoadingCandidateFit(true);
+    api.get<CandidateFit>(`/jobapplications/${jobId}/candidate-fit`, { params: { attachmentIds: selectedAttachmentCsv || undefined, refresh: true } }).then((r) => {
+      candidateFitCache.setCached(`${jobId}:candidate-fit:${selectedAttachmentCsv || "none"}`, r.data);
+      setCandidateFit(r.data);
+      toast("Candidate fit regenerated.", "success");
+    }).catch((error: any) => toast(getApiErrorMessage(error, "Failed to regenerate candidate fit."), "error")).finally(() => setLoadingCandidateFit(false));
+  }, [jobId, selectedAttachmentCsv, candidateFitCache, toast]);
+
   // Match score is deterministic and cheap: load it on the Candidate Fit tab
   // independently of the slow AI narrative so users see the number instantly.
   useEffect(() => {
@@ -348,6 +360,16 @@ export default function JobDetailsDialog({ open, jobId, onClose, initialTab = 0,
     }).catch(() => setFocusPlan(null)).finally(() => setLoadingFocusPlan(false));
   }, [open, jobId, tab, focusPlan, selectedAttachmentCsv, focusPlanCache]);
 
+  const regenerateFocusPlan = useCallback(() => {
+    if (!jobId) return;
+    setLoadingFocusPlan(true);
+    api.get<FocusPlanResponse>(`/jobapplications/${jobId}/focus-plan`, { params: { attachmentIds: selectedAttachmentCsv || undefined, refresh: true } }).then((r) => {
+      focusPlanCache.setCached(`${jobId}:focus-plan:${selectedAttachmentCsv || "none"}`, r.data);
+      setFocusPlan(r.data);
+      toast("Focus plan regenerated.", "success");
+    }).catch((error: any) => toast(getApiErrorMessage(error, "Failed to regenerate focus plan."), "error")).finally(() => setLoadingFocusPlan(false));
+  }, [jobId, selectedAttachmentCsv, focusPlanCache, toast]);
+
   useEffect(() => {
     if (!open || !jobId || tab !== 7 || interviewPrep) return;
     const cacheKey = `${jobId}:interview-prep:${selectedAttachmentCsv || "none"}`;
@@ -1143,6 +1165,11 @@ export default function JobDetailsDialog({ open, jobId, onClose, initialTab = 0,
         {tab === 5 && (
           <Box>
             <MatchScoreCard score={matchScore} loading={loadingMatchScore} />
+            <Box sx={{ display: "flex", justifyContent: "flex-end", my: 1.5 }}>
+              <Button size="small" variant="outlined" disabled={loadingCandidateFit} onClick={regenerateCandidateFit}>
+                {loadingCandidateFit ? "Regenerating..." : "Regenerate"}
+              </Button>
+            </Box>
             {loadingCandidateFit ? <Box sx={{ py: 4, display: "flex", justifyContent: "center" }}><CircularProgress size={28} /></Box> : candidateFit ? (
               <Box sx={{ display: "flex", flexDirection: "column", gap: 2.5 }}>
                 <Typography variant="caption" sx={{ color: "text.secondary", display: "block", mt: -1 }}>{t("jobDetailsAiFitHint")}</Typography>
@@ -1171,6 +1198,11 @@ export default function JobDetailsDialog({ open, jobId, onClose, initialTab = 0,
 
         {tab === 6 && (
           <Box>
+            <Box sx={{ display: "flex", justifyContent: "flex-end", mb: 1.5 }}>
+              <Button size="small" variant="outlined" disabled={loadingFocusPlan} onClick={regenerateFocusPlan}>
+                {loadingFocusPlan ? "Regenerating..." : "Regenerate"}
+              </Button>
+            </Box>
             {loadingFocusPlan ? <Box sx={{ py: 4, display: "flex", justifyContent: "center" }}><CircularProgress size={28} /></Box> : focusPlan ? (
               <Box sx={{ display: "flex", flexDirection: "column", gap: 2 }}>
                 <DraftCard title={t("jobDetailsFocusSummary")} content={focusPlan.strategicSummary} />