refactor(ui): PR #134 review — MetaScreen/ESC chain tightening, D-192 reword

Addresses Tyre's 9 architecture items from the sprint-36 client review.

- decisions/architecture.md (Tyre #1): D-192 now says "deprecate; removal
  tracked in #868" instead of "remove". The branch does not remove the
  version field or guard — that belongs in the coordinated server+client
  PR. The decision text now matches the code on this branch.
- meta_stack.gd (#2): handle_escape() on a screen with
  closable_by_escape=false now consumes the event unconditionally. Was
  returning whatever on_escape() returned, which default-returned false
  and leaked ESC into main.gd's implant/settings chain — opening the
  settings dialog behind the loading screen.
- debug_console.gd (#4): drop the direct KEY_ESCAPE branch in
  _unhandled_input. ESC now falls through to main.gd → MetaStack, which
  finds the console on top of the stack and closes it via the normal
  path. Other keys are still consumed so movement/action can't leak.
- main.gd (#6, #10): extract the ESC priority chain into
  _handle_menu_key() so "MetaStack → implant → settings" is a named
  thing. Add a comment near connect_to_sim explaining that
  GameState.bookmark_catalog survives the Option A scene transition via
  the autoload.
- main_menu.gd (#7): header comment documenting the double LoadingScreen
  lifecycle — safe today because main_menu.tscn and main.tscn never
  co-exist, noted for future promotion to autoload if that changes.
- meta_screen.gd (#8): apply captures_input symmetrically in open()/
  close() — was set in open() only, so a screen changing the flag
  between open+close kept the opened value forever.
- meta_screen.gd (#9): on_escape() docstring clarifies the tri-state
  (consume-and-hold / consume-and-close / ignore) — and that
  closable_by_escape=false is the screen-wide way to say
  "consume-and-hold".
- bug_report_dialog.gd (#11): capture_cancelled now emits from
  on_close() (covers any close path — ESC, MetaStack pop, programmatic
  close) rather than only on_escape(). A new _completed flag
  distinguishes completion from cancel so the two signals stay
  mutually exclusive.

client/ui/meta/meta_stack.gd

@@ -38,12 +38,18 @@ func is_active() -> bool:
 
 ## Handle ESC key. Call from main.gd before HudGroups ESC handling.
 ## Returns true if the event was consumed (callers must return after).
+##
+## A screen on the stack always consumes the event. `closable_by_escape = false`
+## means "I refuse to close on ESC" — not "pass the event through to the
+## implant/gameplay layer." Otherwise an un-escapable screen (e.g. LoadingScreen)
+## would leak ESC to main.gd and open the settings dialog behind it.
 func handle_escape() -> bool:
 	var t = top()
 	if t == null:
 		return false
 	if not t.closable_by_escape:
-		return t.on_escape()
+		t.on_escape()
+		return true
 	if t.on_escape():
 		return true
 	t.close()