v0.8.3: TUI stabilization — box calls, package fixes, sandbox, configure

Bug fixes:
- Fix box() calls: set color-pair before box, pass ACS default chtype integers
- Fix markdown functions: move to passepartout.channel-tui package where
  Croatoan is imported; use add-attributes/remove-attributes instead of
  :bold/:underline kwargs to add-string; call theme-color in gate-trace-lines
  to convert theme keys to Croatoan colors
- Fix sandbox: remove dex:get/dex:post from restricted symbols
  (blocked neuro-provider from loading)
- Export *log-lock* from passepartout (was unbound in jailed skill packages)
- Fix configure: always deploy to XDG, skip cp when source==dest
- Fix bash crash handler format string (~~ escaping)
- Revert test reorder in 28 files (caused package leakage in skill loader)

Design cleanup:
- Extract tui-run-screen from tui-main for clean separation
- Remove inject-stimulus alias
- Merge *backend-registry* into *probabilistic-backends*
- Fix read-framed-message whitespace DoS (4096-iteration max)
- Add *read-eval* nil to dispatcher-approvals-process read-from-string

org/core-package.org

@@ -43,6 +43,8 @@ where to add new exports:
    ;; ── Core: Pipeline ──
    #:main
    #:log-message
+   #:*log-buffer*
+   #:*log-lock*
    #:process-signal
    #:loop-process
    #:perceive-gate