feat(layout-review): journey-level redesign — front door, taught order, consistency

Addresses the journey-level review (the app felt like 12 tools sharing a
stylesheet, not one guided product). File-partitioned changes:

Navigation (shell.js): rename Home -> "Start here" with front-door
emphasis (.dt-nav-start); reorder Data Cleaners into pipeline order
(Clean Text -> Standardize -> Fix Missing -> Find Duplicates); new
"Finance" group (Reconcile, PDF to CSV); all stubs moved to a bottom
"Coming soon" group, no longer interleaved with working tools.

Front door (home.html): a prominent primary "Clean these files for me"
that runs the recommended pipeline in order, above the existing
per-finding cards (reframed as "fix one thing at a time").

Shared tokens (app.css): .dt-next-step suggestion strip + .dt-nav-start.

Teach the order: a slim .dt-next-step strip at the end of each linear
cleaner page points to the next pipeline step (Map Columns -> Start here;
orchestrator/Finance pages correctly omit it).

Local-first: the green "Runs 100% locally" pill now sits in every working
tool page's header (home + 8 tools), where client data is entered.

Plain English: jargon relabeled on input controls (coerce, E.164,
NFC/NFKC, sentinels, survivor rule), technical terms kept in tooltips and
audit/output cells only.

Stubs (06/08/07): rebuilt to one identical skeleton — info line + plain
feature list + a real "Notify me when this ships" button; every disabled
control and uploader removed (a dimmed dropzone reads as broken).

Intake: full dropzone+chip replaced with the compact "Using <file>" banner
on Clean Text, Fix Missing, Find Duplicates, and both Reconcile sides.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

layout-review/04_missing_handler.html

@@ -19,28 +19,27 @@
       <!-- Tool header -->
       <div class="dt-tool-header">
         <h1>Fix Missing Values</h1>
-        <button class="dt-help-btn"><span class="dt-mi">help_outline</span> Help</button>
+        <div style="display:flex;align-items:center;gap:12px;margin-top:6px">
+          <span class="dt-privacy-pill">
+            <svg viewBox="0 0 24 24" fill="none" stroke="currentColor">
+              <rect x="4" y="11" width="16" height="10" rx="2"/>
+              <path d="M8 11V7a4 4 0 018 0v4"/>
+            </svg>
+            Runs 100% locally
+          </span>
+          <button class="dt-help-btn" style="margin-top:0"><span class="dt-mi">help_outline</span> Help</button>
+        </div>
       </div>
       <p class="dt-tool-caption">Find blank cells (even hidden ones) and fill them in or remove them.</p>
 
       <div class="dt-spacer"></div>
 
-      <!-- Upload (file staged) -->
-      <p class="dt-caption">Tip: files imported on the Home screen are picked up here automatically.</p>
-      <label class="dt-label">Import CSV or Excel file</label>
-      <div class="dt-uploader">
-        <div class="dt-uploader-text">
-          <span class="hint"><span class="dt-mi" style="vertical-align:-4px">upload_file</span> Drag and drop file here</span>
-          <span class="sub">Up to 1.5 GB · CSV, TSV, XLSX, XLS</span>
-        </div>
-        <button class="dt-btn">Browse files</button>
-      </div>
-      <div class="dt-file-chip">
-        <span class="dt-file-icon-chip"><svg viewBox="0 0 24 24" fill="none" stroke="currentColor"><path d="M14 2H6a2 2 0 00-2 2v16a2 2 0 002 2h12a2 2 0 002-2V8z"/><path d="M14 2v6h6"/></svg></span>
-        <span class="name">survey_responses.csv</span>
-        <span class="size">684 KB</span>
-        <button class="dt-btn dt-btn-tertiary" title="Remove">✕</button>
+      <!-- File pickup banner (using file from upload screen) -->
+      <div class="dt-alert info">
+        <span class="dt-mi">description</span>
+        <span>Using <strong>survey_responses.csv</strong> from the upload screen.</span>
       </div>
+      <button class="dt-btn" style="margin-bottom:4px">Use a different file</button>
 
       <!-- Preview expander (collapsed after a result exists) -->
       <details class="dt-expander">
@@ -117,9 +116,9 @@
                   <h4>Detection</h4>
                   <div class="dt-check on"><span class="box"><span class="dt-mi">check</span></span> Standardize disguised nulls to NaN</div>
                   <div class="dt-field">
-                    <label class="dt-label">Sentinel values (comma-separated)</label>
+                    <label class="dt-label" title="Sentinel values">Blanks in disguise (N/A, dash, NULL) — comma-separated</label>
                     <div class="dt-input">N/A, n/a, NA, NULL, null, None, -, --, ?, #N/A</div>
-                    <div class="dt-help-text">Matched case-insensitively after stripping whitespace.</div>
+                    <div class="dt-help-text">Text that really means &ldquo;empty.&rdquo; Matched case-insensitively after stripping whitespace.</div>
                   </div>
                 </div>
                 <div>
@@ -253,6 +252,8 @@
         <button class="dt-btn">Download config JSON</button>
       </div>
 
+      <div class="dt-next-step"><span class="dt-mi">arrow_forward</span><span>Missing values handled. Next, most files need: <a href="01_deduplicator.html">Find Duplicates →</a></span><button class="dt-next-step-dismiss" title="Dismiss">✕</button></div>
+
     </div>
   </main>
 </div>