…nses, UI fixes

Keyboard capture (input.rs):
- Lock the framebuffer focus filter so Tab / arrows / Esc reach the guest
  instead of being eaten by egui focus navigation.
- Forward Ctrl+C/X/V (egui-winit otherwise swallows them as clipboard
  commands), map F5, and let Ctrl+Alt+F11 send a bare F11 to IRIX.

Sandbox CHD consolidation (the fold needs folder, not file, access):
- handle.rs surfaces the fold error instead of swallowing it.
- Start + disk-assignment preflight (dir_writable probe) and a ChdGrantModal
  that prompts for a recursive folder grant, with a dedicated-folder tip.
- Auto-consolidate on a clean guest power-off (cpu_stopped edge), since macOS
  Cmd+Q bypasses the close-time fold (winit 0.29 has no
  applicationShouldTerminate).

Local sandboxed build (test the App Sandbox without the App Store):
- installer/iris-gui-sandbox-local.entitlements + `build-macos.sh appstore`
  (builds --features appstore, signs with app-sandbox).

GUI:
- Fix tofu glyphs: status dots are now sized bullets (U+2022); replaced
  U+25CF/2713/2717/2715/1F5C2/23FB and U+2192 with rendering equivalents.
- Build-features panel reports "jit: off (sandbox)" at runtime.
- Rename-machine is now a modal (the in-menu text box reset every frame).
- Config editor fills the pane when idle; header shows "Configuration — <name>".
- Help: Licenses... shows BSD-3-Clause (IRIS) plus GPL-3.0 (libchdman-rs/CHD)
  with source links, and Privacy policy... — both embedded via include_str!.
- Reworded "the serial console is NOT the network", removed "for App Review",
  renamed "Network test" to "Serial console".

LICENSE-GPL3.txt brought onto this branch (CHD builds are conveyed under
GPL-3.0). Findings written up under rules/gui and rules/macos.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>