find/replace: editor (Ctrl+H/F) + board-wide (Ctrl+Shift+H)

Editor find/replace (public/js/modules/editor.js, public/index.php):
* New #editor-find-bar inside #editor-pane (above the textarea, pushes
  it down via flex-col). Two rows: find input + match count + prev/next
  + close, and replace input + replace-one + replace-all.
* Ctrl+H opens find+replace, Ctrl+F opens find-only (replace row
  hidden). Same shortcut toggles off if already open in the same mode.
* runFind(): case-insensitive indexOf scan, all match positions stored.
  jumpTo() sets textarea.setSelectionRange for the Nth match.
  findNext/findPrev cycle with wrap-around.
* replaceOne(): body.setRangeText at the current match position, re-scan.
  replaceAll(): regex-based global replace on body.value.
* Enter in find input = next (Shift+Enter = prev). Enter in replace
  input = replace one. Escape closes the bar + refocuses textarea.
* closeModal() calls closeFindBar() to clean up on editor close.

Board-wide find/replace (public/js/app.js):
* Ctrl+Shift+H opens a centered overlay that fetches all cards with
  full bodies (api('api/cards'), bypasses lazy-load).
* Live search: typing in the find input scans all card bodies case-
  insensitive. Matches shown as a scrollable list with color dot,
  card title, occurrence count, and a context snippet with <mark>
  highlight around the first match.
* Status line: "12 occurrences in 5 cards" or "no matches".
* Replace All button (danger-styled, disabled until both inputs have
  text and matches exist). Click opens a showDialog confirmation:
  "Replace 12 occurrences of 'foo' with 'bar' across 5 cards?"
  On confirm: regex replace per card body → PATCH → _reloadAll.
* Escape / click-outside / Close button dismiss the overlay.

Shortcuts registered in the central registry for the help screen:
* ⌃ H (editor), ⌃ F (editor), ⌃ ⇧ H (global board-wide).

Tests (public/plugins/tests/board-find-replace.test.js):
* Ctrl+Shift+H opens the overlay (polls for #board-find-replace).
* Typing in find shows matching cards (creates 3 cards, 2 match,
  asserts status count + list contains matching titles + excludes
  non-matching title).
* Replace all updates card bodies after confirmation (creates 2
  cards with "hello", replaces with "goodbye", confirms dialog,
  verifies via API that bodies are "goodbye world goodbye" and
  "goodbye there").
* Replace all button disabled without replace text.

detail.test.js: "closes on ESC" stabilized — guard that detail is
actually open before dispatching Escape, poll (20×50ms) instead of
fixed sleep(150) for the .open class to be removed.

chore: bump version to 0.9.21

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

public/index.php

@@ -2155,9 +2155,28 @@ if (str_starts_with($route, '/api/')) {
             </div>
             <div class="flex flex-1 min-h-0 overflow-hidden">
                 <div id="editor-gutter" class="hidden bg-t-bg text-t-dim text-right font-mono text-sm select-none shrink-0 border-r border-t-border" style="width:3.5em; padding:1rem 0.25rem 1rem 0.5rem; overflow-y:scroll; scrollbar-width:none; -ms-overflow-style:none;"></div>
-                <div id="editor-pane" class="relative min-h-full bg-t-bg overflow-hidden" style="flex:1 1 0%;min-width:0;">
-                    <div id="editor-line-hl" class="absolute pointer-events-none left-0 right-0" style="background:var(--t-border);opacity:0.18;display:none;z-index:1;"></div>
-                    <textarea id="editor-body" placeholder="> write markdown..." class="absolute inset-0 w-full h-full text-t-text text-sm font-mono placeholder:text-t-dim border-none overflow-y-auto" style="padding:1rem; line-height:1.625; resize:none; z-index:2; background:transparent;"></textarea>
+                <div id="editor-pane" class="relative min-h-full bg-t-bg overflow-hidden flex flex-col" style="flex:1 1 0%;min-width:0;">
+                    <!-- Find / Replace bar (Ctrl+H) -->
+                    <div id="editor-find-bar" class="hidden shrink-0 border-b border-t-border bg-t-surface px-3 py-2" style="z-index:5;">
+                        <div class="flex items-center gap-2 mb-1.5">
+                            <i class="ph ph-magnifying-glass text-xs text-t-dim"></i>
+                            <input id="find-input" type="text" placeholder="find…" class="flex-1 bg-t-bg border border-t-border text-t-bright text-xs px-2 py-1 font-mono focus:border-t-accent focus:outline-none" style="min-width:0;">
+                            <span id="find-count" class="font-pixel text-[9px] text-t-dim" style="min-width:50px;text-align:center;"></span>
+                            <button id="find-prev" class="toolbar-btn" title="previous"><i class="ph ph-caret-up text-xs"></i></button>
+                            <button id="find-next" class="toolbar-btn" title="next"><i class="ph ph-caret-down text-xs"></i></button>
+                            <button id="find-close" class="toolbar-btn" title="close"><i class="ph ph-x text-xs"></i></button>
+                        </div>
+                        <div id="replace-row" class="flex items-center gap-2">
+                            <i class="ph ph-swap text-xs text-t-dim"></i>
+                            <input id="replace-input" type="text" placeholder="replace…" class="flex-1 bg-t-bg border border-t-border text-t-bright text-xs px-2 py-1 font-mono focus:border-t-accent focus:outline-none" style="min-width:0;">
+                            <button id="replace-one" class="font-pixel text-[9px] px-2 py-1 border border-t-border text-t-muted hover:border-t-accent hover:text-t-accent transition-colors">Replace</button>
+                            <button id="replace-all" class="font-pixel text-[9px] px-2 py-1 border border-t-border text-t-muted hover:border-t-accent hover:text-t-accent transition-colors">All</button>
+                        </div>
+                    </div>
+                    <div class="relative flex-1 min-h-0">
+                        <div id="editor-line-hl" class="absolute pointer-events-none left-0 right-0" style="background:var(--t-border);opacity:0.18;display:none;z-index:1;"></div>
+                        <textarea id="editor-body" placeholder="> write markdown..." class="absolute inset-0 w-full h-full text-t-text text-sm font-mono placeholder:text-t-dim border-none overflow-y-auto" style="padding:1rem; line-height:1.625; resize:none; z-index:2; background:transparent;"></textarea>
+                    </div>
                 </div>
                 <div id="editor-divider" class="hidden shrink-0" style="width:11px;cursor:col-resize;position:relative;z-index:3;margin:0 -5px;"><div style="position:absolute;left:5px;top:0;bottom:0;width:1px;background:var(--t-border);"></div><div style="position:absolute;top:50%;left:50%;transform:translate(-50%,-50%);width:4px;height:48px;border-radius:2px;background:var(--t-muted);opacity:0.08;transition:opacity 0.2s;"></div></div>
                 <div id="editor-preview" class="bg-t-bg p-4 overflow-y-auto hidden" style="flex:1 1 0%;min-width:0;"><div id="preview-content" class="prose text-sm text-t-text"></div></div>