Add Formula Library ratings, Job Profitability report, and Quote Revision History improvements

- Formula Library ratings: thumbs up/down per company per formula; toggle on/off; sorts by net score; own formulas not rateable; FormulaLibraryRating entity + migration AddFormulaLibraryRatings
- Job Profitability report: actual labor cost (logged hours x StandardLaborRate) vs powder cost vs billed price per job; gross margin % color-coded; time-tracked-only filter; totals footer
- Quote Revision History: track Total price changes on every save; log Sent/Resent events with recipient email; replace flat table with grouped timeline UI (icons per event type, total-change badge on header)
- Setup Wizard: cap CompletedCount at TotalSteps so old 10-step data no longer shows 10/5
- Formula Library card: fix badge overflow on long titles; add Rate: label to make voting buttons discoverable
- Help docs and AI knowledge base updated for all three features

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/PowderCoating.Web/Views/Help/Reports.cshtml

@@ -168,6 +168,34 @@
                 stage may need more capacity.
             </p>
 
+            <h3 class="h6 fw-semibold mt-3 mb-2">Job Profitability Report</h3>
+            <p>
+                Compares each job&rsquo;s billed price against its direct costs so you can see your gross margin per job.
+                Access it from <strong>Reports &rarr; Job Profitability</strong>.
+            </p>
+            <ul class="mb-3">
+                <li class="mb-1"><strong>Billed</strong> &mdash; the job&rsquo;s final price as quoted.</li>
+                <li class="mb-1"><strong>Collected</strong> &mdash; how much has actually been paid on the linked invoice.</li>
+                <li class="mb-1"><strong>Hours</strong> &mdash; actual hours logged via the job&rsquo;s Time Log entries.</li>
+                <li class="mb-1"><strong>Labor Cost</strong> &mdash; logged hours &times; your Standard Labor Rate (set in Company Settings).</li>
+                <li class="mb-1"><strong>Powder Cost</strong> &mdash; estimated from pounds-to-order &times; cost-per-lb on each coat. Uses <em>actual pounds used</em> when recorded.</li>
+                <li class="mb-1"><strong>Gross Margin</strong> &mdash; Billed minus estimated total cost. Color-coded: green &ge;40%, yellow &ge;20%, red below 20%.</li>
+            </ul>
+            <p>
+                Use the <strong>Time-tracked jobs only</strong> toggle to filter out jobs with no time entries &mdash; jobs
+                without time entries show $0 labor cost, which skews the average margin downward. Log time entries on any
+                job via <strong>Job Details &rarr; Time Log</strong>.
+            </p>
+            <div class="alert alert-permanent alert-info d-flex gap-2 mb-3" role="alert">
+                <i class="bi bi-info-circle flex-shrink-0 mt-1"></i>
+                <div>
+                    This report covers <strong>direct costs only</strong> (labor + powder). Overhead, equipment time,
+                    and prep costs are factored into your quoted price via operating cost rates but are not broken out
+                    separately here. Use it as a relative indicator &mdash; which jobs are thin vs. comfortable &mdash;
+                    rather than an absolute profitability figure.
+                </div>
+            </div>
+
             <h3 class="h6 fw-semibold mt-3 mb-2">Powder Usage Report</h3>
             <p>
                 Tracks powder consumption by inventory item and by job. Useful for verifying that actual