docs(site): [SITE-04] document Canvas and Mediabunny proxies

refactor/changes/2026-09-16-SITE-04-proxies-guides.md

@@ -0,0 +1,50 @@
+# SITE-04 checkpoint: Canvas and Mediabunny guides
+
+Four bilingual guides replace external-only proxy navigation destinations while
+retaining the original Canvas and Mediabunny examples. New route provenance
+records pre-change HEAD e2bd7c97424df216cbf1486bb6c60ccd70af5c2f. These pages
+describe the unreleased branch, not a published capability guarantee.
+
+Canvas documents real-video decoding, Canvas member priority, synchronous callback
+ordering, native-event forwarding, geometry, subtitle track placement, bitmap and
+stream ownership, and six public types with the approved old-root/runtime split.
+Mediabunny documents all13 top-level options, both HLS menu configurations, track
+pairing/state, all declared shim members, synthetic frame/range semantics and
+11 public types. Inert setters, crossOrigin not configuring SDK fetch, Auto not
+implying bandwidth adaptation, Range preflight's independent error path and
+partial versus wholly undecodable input are stated explicitly. See the
+[source/member tracker](../site-content-review.md).
+
+## Verification
+
+- Node24.21.0, Yarn1.22.22 and TypeScript5.9.3. Four exact TS snippets pass strict
+  NodeNext, skipLibCheck:false and types:[]. Four Run Code blocks match original
+  demo files exactly. Canvas pages validate42 distinct local file/fragment targets;
+  Mediabunny pages validate43.
+- All12 guide cases pass on Chromium153.0.8010.12, Firefox155.0 and Windows
+  WebKit26.6 without retries/page errors: HTTP load, sidebar destination, visible
+  Run Code, exact source/library forwarding and language switching. Popup editor
+  responses are isolated; this is not video decoding, HLS playback, media event
+  ordering or physical-device acceptance. Screenshots retained; Chromium Chinese
+  Canvas inspected for layout and control visibility.
+- Existing documentation/loading tests:17 pass,0 failures/skips,1302.5949ms.
+  Config lint, inventory and demo route checks, build:llm/check:llm and build:docs
+  pass. VitePress9.12s, Yarn10.66s. No dependency or project script added.
+- Current inventory:66 Markdown (33 per language),75 HTML,30 examples,
+  963 enumerated core declaration members and204 assets. All16 plugins, two tools
+  and two proxies now have dedicated bilingual guides. This is not a claim of
+  complete core semantic coverage or final demo acceptance.
+- All21 library candidate build envelopes remain valid; package runtime, public
+  declarations, packaged documentation and dependency inputs are unchanged.
+
+See [the evidence record](../baselines/site04-proxies-guides.json). Generated
+outputs came from repository scripts. SITE-04 stays doing, totals224/22/39.
+Next cross-check earlier Danmuku/HLS/DASH/Audio/VTT guides and core member semantics.
+User-directed formal reviews, SDK/media/device gates and publication stay separate.
+No push, remote dispatch, deployment or publication occurred. Revert this checkpoint
+to restore previous navigation and generated assets without changing package APIs.
+
+Full staged whitespace checking exits2 for eight whitespace-only template lines
+in the four new generated HTML files. Exact paths/lines and blank content were
+inspected; excluding only those files passes. Generated HTML is preserved and
+the full check is not reported as passing. See the evidence record.