feat: integrate Modal Closer as injected browser script (#27)

Port the modalcloser abx-plugin as a SingleFile --browser-script rather
than a spawned Puppeteer daemon. No external extension download required.

Core behavior (singlefile.rs):
- MODAL_CLOSER_DIALOG_OVERRIDES: main-world <script> bridge (best-effort;
  blocked by strict script-src CSP) that overrides window.alert/confirm/
  prompt/print, nulls window.onbeforeunload, traps its setter, and wraps
  window.addEventListener to no-op 'beforeunload' registrations.
- MODAL_CLOSER_POLLING_SETUP: defines _archivr_mc_run() which runs two
  passes on every tick (immediate first run, then setInterval every 500 ms
  matching MODALCLOSER_POLL_INTERVAL default):
    Pass 1 (best-effort, CSP-sensitive): main-world <script> bridge calls
    Bootstrap/jQuery/jQuery UI/SweetAlert teardown APIs.
    Pass 2 (always, CSP-immune): isolated-world DOM mutations — Escape-key
    dispatch (Radix/Headless UI/Angular Material), backdrop clicks, full
    CSS selector hiding for 40+ named consent/overlay vendors, body
    scroll-lock reset. Direct DOM mutations need no inline script execution.
- resolve_modal_closer_config(): reads ARCHIVR_MODAL_CLOSER env var
  (default true); no external resource required.
- modal_closer_enabled: Option<bool> in CaptureConfig so Default::default()
  yields None (follow env var) rather than false.

Schema (database.rs):
- modal_closer_enabled column in auth DB instance_settings (default 1).
- Idempotent ALTER TABLE migration for existing databases.
- get/update_instance_settings updated (SELECT col 6, UPDATE param ?7).

HTTP (routes.rs):
- modal_closer_enabled in CaptureBody and UpdateInstanceSettingsBody.
- Per-capture body overrides global setting which overrides env var.

Frontend:
- SettingsView ExtensionsTab: third ext-card for Modal & Dialog Closer.
- CaptureDialog: per-capture toggle in Advanced Options, state initialized
  from server default, included in submitCapture payload.
- api.js: submitCapture forwards modal_closer_enabled to capture body.

Behavior vs original modalcloser daemon:
- Functionally identical on non-strict-CSP pages (the large majority).
- Gap: <script> bridge is subject to page CSP; page.evaluate() is not.
  On strict-CSP pages framework teardown and dialog overrides are no-ops;
  CSS selector hiding and Escape dispatch (Pass 2) always work.
- Gap: alert/confirm/prompt overridden to instant no-op vs CDP timed
  dialog.accept() with 1250 ms delay; irrelevant for archival in practice.

frontend/src/api.js

@@ -122,11 +122,12 @@ export async function fetchTags(archiveId) {
 export async function submitCapture(archiveId, locator, quality = null, extensions = null) {
   const payload = { locator }
   if (quality && quality !== 'best') payload.quality = quality
-  // extensions: { ublock_enabled?: bool, reader_mode?: bool } — per-capture overrides
+  // extensions: { ublock_enabled?: bool, reader_mode?: bool, cookie_ext_enabled?: bool, modal_closer_enabled?: bool }
   if (extensions) {
     if (typeof extensions.ublock_enabled === 'boolean') payload.ublock_enabled = extensions.ublock_enabled
     if (typeof extensions.reader_mode === 'boolean') payload.reader_mode = extensions.reader_mode
     if (typeof extensions.cookie_ext_enabled === 'boolean') payload.cookie_ext_enabled = extensions.cookie_ext_enabled
+    if (typeof extensions.modal_closer_enabled === 'boolean') payload.modal_closer_enabled = extensions.modal_closer_enabled
   }
   const res = await fetch(`/api/archives/${archiveId}/captures`, {
     method: "POST",

frontend/src/components/CaptureDialog.jsx

@@ -122,6 +122,7 @@ export default function CaptureDialog({ open, archiveId, onClose, onCaptured, on
   const [globalSettings, setGlobalSettings] = useState(null)
   // Cookie consent: session-level only, initialized from server default
   const [cookieExtEnabled, setCookieExtEnabled] = useState(true)
+  const [modalCloserEnabled, setModalCloserEnabled] = useState(true)
 
   // Load global settings from server once on mount
   useEffect(() => {
@@ -129,6 +130,7 @@ export default function CaptureDialog({ open, archiveId, onClose, onCaptured, on
       .then(s => {
         setGlobalSettings(s)
         setCookieExtEnabled(s.cookie_ext_enabled ?? true)
+        setModalCloserEnabled(s.modal_closer_enabled ?? true)
       })
       .catch(() => setGlobalSettings({}))
   }, [])
@@ -299,7 +301,7 @@ export default function CaptureDialog({ open, archiveId, onClose, onCaptured, on
     const qual = item.quality || 'best'
     setItems(prev => prev.map(it => it.id === item.id ? { ...it, status: 'submitting', error: null } : it))
     try {
-      const extensions = { ublock_enabled: ublockEnabled, reader_mode: readerMode, cookie_ext_enabled: cookieExtEnabled }
+      const extensions = { ublock_enabled: ublockEnabled, reader_mode: readerMode, cookie_ext_enabled: cookieExtEnabled, modal_closer_enabled: modalCloserEnabled }
       const job = await submitCapture(aid, loc, qual, extensions)
       setItems(prev => prev.map(it =>
         it.id === item.id ? { ...it, status: 'running', jobUid: job.job_uid, archiveId: aid } : it
@@ -499,6 +501,22 @@ export default function CaptureDialog({ open, archiveId, onClose, onCaptured, on
                   <span className="ext-toggle-knob" />
                 </button>
               </label>
+              <label className="capture-ext-row" style={{ marginTop: 8 }}>
+                <span className="capture-ext-label">
+                  <span className="capture-ext-name">Close modals and dialogs</span>
+                  <span className="capture-ext-desc">Auto-dismiss cookie banners and overlays during this capture</span>
+                </span>
+                <button
+                  type="button"
+                  role="switch"
+                  aria-checked={modalCloserEnabled}
+                  className={`ext-toggle ext-toggle--sm${modalCloserEnabled ? ' ext-toggle--on' : ''}`}
+                  onClick={() => setModalCloserEnabled(v => !v)}
+                  aria-label="Toggle modal closer for this capture"
+                >
+                  <span className="ext-toggle-knob" />
+                </button>
+              </label>
             </div>
           )}
         </div>

frontend/src/components/SettingsView.jsx

@@ -683,12 +683,27 @@ function ExtensionsTab() {
     }
   }
 
+  async function toggleModalCloser(val) {
+    setSaving(true)
+    setMsg(null)
+    try {
+      await updateInstanceSettings({ modal_closer_enabled: val })
+      setSettings(s => ({ ...s, modal_closer_enabled: val }))
+      setMsg({ ok: true, text: 'Saved.' })
+    } catch (e) {
+      setMsg({ ok: false, text: e.message })
+    } finally {
+      setSaving(false)
+    }
+  }
+
   if (loading) return <div className="muted">Loading\u2026</div>
 
   const extAvailable = settings?.ublock_ext_available ?? false
   const extEnabled = settings?.ublock_enabled ?? true
   const cookieExtAvailable = settings?.cookie_ext_available ?? false
   const cookieExtEnabled = settings?.cookie_ext_enabled ?? true
+  const modalCloserEnabled = settings?.modal_closer_enabled ?? true
 
   return (
     <div>
@@ -756,6 +771,30 @@ function ExtensionsTab() {
               </button>
             </div>
           </div>
+
+          <div className="ext-card">
+            <div className="ext-card-header">
+              <div className="ext-card-info">
+                <span className="ext-card-name">Modal &amp; Dialog Closer</span>
+                <span className="ext-card-desc">
+                  Auto-dismiss cookie banners, consent overlays, and other modal dialogs
+                  before a WebPage capture is taken. Implemented as an injected browser
+                  script; no external extension required.
+                </span>
+              </div>
+              <button
+                type="button"
+                role="switch"
+                aria-checked={modalCloserEnabled}
+                className={`ext-toggle${modalCloserEnabled ? ' ext-toggle--on' : ''}`}
+                onClick={() => toggleModalCloser(!modalCloserEnabled)}
+                disabled={saving}
+                aria-label="Toggle Modal and Dialog Closer"
+              >
+                <span className="ext-toggle-knob" />
+              </button>
+            </div>
+          </div>
         </div>
 
         {msg && <div className={`form-msg form-msg--${msg.ok ? 'ok' : 'err'}`}>{msg.text}</div>}