Restructure Settings nav, modernize import page, dedup/genres UX polish

Settings is now one top-nav entry with Credentials and Jobs as sidebar
sub-pages (jobs moved from /jobs to /settings/jobs). Manual import page
replaces the bare file input and free-text filename field with a drag-drop
dropzone and a proper file-picker table. Genres page drops the "force"
checkbox for two explicit buttons (Preview / Fix genres now). Dedup's
"Scan now" runs both the file-naming and acoustic passes together, and the
table labels which pass caught each candidate instead of showing the raw
pass name. .btn-ghost gets a visible border so it reads as a real button
next to Delete/Danger actions instead of looking unaligned. Job names
throughout the UI are now human-readable instead of raw job_key strings.

Also includes the fpcalc exit-code fix from earlier (fingerprint index
was discarding valid fingerprints on files with a benign decode warning).

app/templates/jobs/index.html

@@ -1,14 +1,7 @@
-{% extends "base.html" %}
-{% block title %}Jobs — alembic{% endblock %}
-{% block content %}
-<div class="page-header">
-  <div>
-    <h1>Jobs</h1>
-    <p class="subtitle muted">Maintenance runs on their own schedule, or trigger them manually here.</p>
-  </div>
-</div>
-
-<h2>Maintenance jobs</h2>
+{% extends "settings/_layout.html" %}
+{% block settings_title %}Jobs{% endblock %}
+{% block settings_content %}
+<h2 style="margin-top:0;">Maintenance jobs</h2>
 <div class="table-wrap scroll">
   <table>
     <thead><tr><th>Job</th><th>Status</th><th>Next run</th><th></th></tr></thead>
@@ -16,16 +9,16 @@
       {% for job in maintenance_jobs %}
       <tr>
         <td>
-          <div class="mono">{{ job.job_key }}</div>
-          {% if job.description %}<div class="muted" style="font-size:0.8em; margin-top:0.15rem;" title="{{ job.description }}">{{ job.description }}</div>{% endif %}
+          <div title="{{ job.job_key }}">{{ job.label }}</div>
+          {% if job.description %}<div class="muted" style="font-size:0.8em; margin-top:0.15rem;">{{ job.description }}</div>{% endif %}
         </td>
         <td>{% if job.enabled %}<span class="badge badge-success">enabled</span>{% else %}<span class="badge badge-muted">disabled</span>{% endif %}</td>
         <td class="muted mono">{{ job.next_run }}</td>
         <td class="actions-cell">
-          <form method="post" action="/jobs/{{ job.job_key }}/run" class="inline">
+          <form method="post" action="/settings/jobs/{{ job.job_key }}/run" class="inline">
             <button type="submit" class="btn btn-sm">Run now</button>
           </form>
-          <form method="post" action="/jobs/{{ job.job_key }}/toggle" class="inline">
+          <form method="post" action="/settings/jobs/{{ job.job_key }}/toggle" class="inline">
             <button type="submit" class="btn btn-sm btn-ghost">{{ "Disable" if job.enabled else "Enable" }}</button>
           </form>
         </td>
@@ -40,7 +33,7 @@
 <div class="table-wrap scroll">
   <table>
     <thead><tr><th>Job</th><th>Status</th><th>Triggered by</th><th>Summary</th><th></th></tr></thead>
-    <tbody id="runs-tbody" hx-get="/jobs/_runs_table" hx-trigger="every 5s" hx-swap="innerHTML">
+    <tbody id="runs-tbody" hx-get="/settings/jobs/_runs_table" hx-trigger="every 5s" hx-swap="innerHTML">
       {% include "jobs/_runs_table.html" %}
     </tbody>
   </table>