v0.311.0: after a power cut, an app repairs the files the cut left empty; the household sees lost photos (R-1007)

New template block after_unclean_boot (decision 236): once per controller start that followed an
UNCLEAN host boot (crashboot's own verdict, after the 15-minute crash grace; a normal or unknown boot
never runs it), each app with the block rebuilds ONLY its zero-byte files (scan: regular files, no
symlinks, its own filesystem; ids appended to the app's own command in batches; one retry, then
reported) and its own lost-file check is read. The household sees lost files (name, date taken) on
the app page until dismissed; the operator gets app_repaired_after_crash with counts only. Skips,
with the reason, an unproven image, an unknown key, an app not running. MinAgent 0.155.0 unchanged.
Tests red-proofed (14 guards). One new parity fixture (the new card only).

Claude-Session: https://claude.ai/code/session_012qRErfCoiTkvDK9N5XHbzb

controller/internal/web/templates/app_info.html

@@ -28,6 +28,21 @@
     </div>
 </div>
 
+{{- if .LostFiles}}
+<div class="app-info-card alert-warning" style="margin-top:1rem" id="lost-files-card">
+    <h3>{{T "app_info.lost_files_title"}}</h3>
+    <p>{{T "app_info.lost_files_text"}}{{if .LostBootAt}} <strong data-lost-boot-at>{{.LostBootAt}}</strong>{{end}}</p>
+    <ul data-lost-files>
+    {{- range .LostFiles}}
+        <li><span class="mono">{{.Name}}</span>{{if .Taken}} — {{T "app_info.lost_files_taken"}} {{.Taken}}{{end}}</li>
+    {{- end}}
+    </ul>
+    <p>{{T "app_info.lost_files_hint"}}</p>
+    <button type="button" class="btn btn-sm btn-outline" onclick="appPress(this, '/apps/{{.Meta.Slug}}/lost-files/dismiss')">{{T "app_info.lost_files_dismiss_btn"}}</button>
+    <span class="form-hint app-press-err" style="display:none;color:var(--red)"></span>
+</div>
+{{- end}}
+
 {{if .Stack.Updating}}
 <div class="alert alert-info" style="margin-top:1rem" data-update-phase="{{.Stack.UpdatePhase}}">{{updatePhaseText .Stack}}</div>
 {{else if and .Stack.HoldReason (eq .Stack.HoldKind "unhealthy_stop")}}
@@ -350,7 +365,7 @@ function icCopyPw(btn) {
 {{end}}
 
 {{template "layout_end" .}}
-{{- if or .SetupGateClosed .SignupClosed .CloseSignupOffered (and .Stack.Deployed .KnownLoginLine)}}
+{{- if or .SetupGateClosed .SignupClosed .CloseSignupOffered (and .Stack.Deployed .KnownLoginLine) .LostFiles}}
 <script>
 // v0.280.0: the household's presses on this page — "Done, I set it up" (decision 46), "I changed it" (R-710).
 function appPress(btn, url) {