fix(media): record per-attachment media dispositions and render bounded skip markers (#122098)

Inbound image, audio, and video attachments could vanish with no recorded outcome and no model-visible explanation: attachments dropped by first-only selection, disabled or unconfigured capabilities, stage failures, URL-only images, and ACP-undelivered images all left the model unaware the media existed. Fixes #122044; completes the outcome custody started for documents in #122025.

Media capabilities now record one closed disposition per pre-truncation candidate at the decision site that owns the reason, with a memoized lazy native-vision probe (fires only when a marker could render; failure yields unknown and never alters outcomes; explicit image models never pay a catalog lookup). One late reader renders bounded, actionable markers from recorded facts only: native-vision and ACP-delivered images suppress per verified index, recorded failures always render, and document plus media markers share one five-marker budget with a reason-neutral overflow summary. The shipped SDK decision type stays additive (optional dispositions map).

Proof: 906 + 103 focused tests including nine adversarial-review regressions, ClawSweeper local review clean (round 9, zero findings, security cleared), live Telegram image drive showing ref preservation with no false marker.

Co-authored-by: Ayaan Zaidi <hi@obviy.us>

docs/.generated/plugin-sdk-api-baseline/plugin-runtime.json

@@ -1 +1 @@
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