chore: sync tauri-runtime-cef from upstream feat/cef

[github-actions]

Automated sync from tauri-apps/tauri feat/cef branch.

If this PR has merge conflicts, the upstream changed runtime.rs or webview.rs in a way that requires manual porting of the overlay modules. Fix conflicts and merge.

Before merging, read the divergence report below. Re-applying fork patches by hand is how upstream fixes get dropped silently — the report is the only place they surface, because the copy overwrites the evidence.

CEF version: check the cef pin in Cargo.toml, bump Sable's src-tauri/Cargo.toml to match.

Note: if syncing from amr/cef-gtk4, the Cargo.toml will reference gtk4 and winit-gtk4, the fork's overlay config may need updating to handle the gtk4 crate name and the winit git dep.

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Divergence report

Fork-only files (6)

Not in upstream, so they survive the copy and never show in this PR's diff.

• examples/stream_probe.rs
• examples/sw_probe.rs
• src/compat.rs
• src/config.rs
• src/policy.rs
• src/streaming.rs

Upstream items not present in the fork (18)

Each is either a deliberate fork removal or an upstream fix a previous sync dropped. Deliberate removals in this repo always carry a comment explaining why — an entry you cannot find a rationale for is a regression.

File	Kind	Item
src/platform/windows/webview.rs	const	PIN_Z_ORDER_SUBCLASS_ID
src/platform/windows/webview.rs	const	Z_ORDER_PINNED
src/platform/windows/webview.rs	const	Z_ORDER_UNPINNED
src/platform/windows/webview.rs	fn	pin_z_order_subclass_proc
src/platform/windows/webview.rs	fn	raise_to_top
src/platform/windows/webview.rs	fn	set_z_order_pinned
src/runtime.rs	enum	DesktopDeepLinks
src/runtime.rs	enum	RuntimeInitAttribute
src/runtime.rs	fn	custom_scheme_url
src/runtime.rs	fn	navigate_first_webview
src/runtime.rs	struct	NewWindowOpener
src/runtime.rs	type	PlatformSpecificInitAttribute
src/runtime.rs	type	PlatformSpecificWebviewAttribute
src/runtime.rs	type	Webview
src/runtime.rs	type	WindowOpener
src/webview.rs	enum	RuntimeStyle
src/webview.rs	enum	WebviewAtribute
src/window_builder.rs	fn	no_redirection_bitmap