…e[srcdoc]

Closes red-team audit items #9 and #11 from #203. The rule previously only
covered <iframe src=…> with a cross-origin http(s) URL; this broadens it to
cover the same agent-side threat carried by:

- cross-origin <object data=…> and <embed src=…> (same SOP-bypass shape as
  a cross-origin iframe), and
- iframe[srcdoc] regardless of origin — the inline HTML body wasn't authored
  as part of the host page, so an agent walking the DOM can still ingest
  external content even though srcdoc inherits the embedding origin.

srcdoc takes precedence over src per spec, so a srcdoc iframe with a
cross-origin src is redacted via the srcdoc (inline) branch — the placeholder
reflects inline content rather than a misleading cross-origin label.

Popup label renamed from "Hide Cross-Origin Frames" to "Hide Embedded Frames"
to reflect the broader coverage. Rule ID is unchanged so user settings carry
over.

Adds a fast-check property test for the iframe/object/embed boundary per the
repo convention.

Co-authored-by: Claude Opus 4.7 (1M context) <[email protected]>

…dened rule

Exercises the two new branches of cross-origin-frame-redact added in this PR:

- "From the brand" section embeds an <iframe srcdoc=…> whose inline HTML
  carries an AGENT NOTE payload. srcdoc inherits the host origin, so it
  isn't a SOP bypass, but the body lands in the DOM as content an agent
  can ingest. With the extension off the brand copy + agent note render;
  with it on, the rule replaces the whole iframe with a placeholder.

- "Spec sheet" section embeds a cross-origin <object data=https://specs.…>.
  The synthetic CDN doesn't resolve, so the browser falls back to the
  <object>'s children — also an instruction-shaped payload. The rule
  redacts the entire <object>, fallback included.

Updates the demo README's per-page rule table to list cross-origin-frame-redact
on the product detail row alongside social-embed-redact.

Co-authored-by: Claude Opus 4.7 (1M context) <[email protected]>

Update agent-browser-shield-config SKILL.md to reflect the broadened
cross-origin-frame-redact behavior: srcdoc iframes are now redacted (not
left alone), and cross-origin <object>/<embed> are covered too.

Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>

…igin_as_fallback

srcdoc inherits the embedding origin so isn't the Roesner SOP-bypass
threat, and the manifest's `match_origin_as_fallback: true` setting
means every rule already runs inside the srcdoc frame on its own.
Redacting the whole iframe from the parent treats authored-by-the-page
content as if it were untrusted cross-context.

Keeps the object/embed extension (item #9) — those carry the same
SOP-bypass shape as a cross-origin iframe when their data/src loads a
cross-origin resource.

Reverts the popup label rename back to "Hide Cross-Origin Frames
(Experimental)" since srcdoc is no longer covered.

Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>