Bundles the pending TUI work into a coherent batch. Bug fixes from
external review:
* expandPlaceholders: single-pass alternation regex over the original
input prevents `#p\d+` / `#img\d+` tokens inside pasted content from
being re-expanded after the bracket form is inlined.
* /incognito: gate savePromptHistory and the Ctrl+V image-write branch
on `!m.incognito` so the no-persistence contract holds.
* history.txt: write at mode 0600 (chmod existing 0644 files), create
parent dir at 0700, truncate to 500 entries on every save, slog.Warn
on errors instead of swallowing.
* triggerPickerAction: guard m.config.Engine before SetModel, matching
the /model handler.
* Picker key handler: navigation/enter/q consume, escape/ctrl+c close
the picker AND fall through to global handlers (so streaming cancel
and double-tap quit work with an overlay open), default swallows
stray input.
* Paste line count: report total non-empty lines instead of newline
count, ignoring trailing newlines (no more "+0 lines" for "abc").
* Ctrl+O restored to expand-output; Ctrl+Y is the new copy-response
bind. /keys help text updated; picker help entries reordered.
* Tighter perms on .gnoma/pasted_image_*.png (0600).
Race-safety refactor: ApplyTheme used to mutate ~25 package-level
lipgloss styles in place. Replaced with an immutable themeStyles
snapshot and atomic.Pointer[themeStyles] swap. Readers go through a
theme() helper (one atomic load) instead of touching package vars
directly. No locks, no nested-RLock risk if rendering ever moves
off-thread.
Includes pre-existing in-flight work: TUISection in config with
persistent theme/vim settings; /copy /theme /vim slash commands;
provider-name completion; session.SetProvider for the provider picker.
Tests: placeholder_test.go (6 regression + happy-path cases including
the pasted-content collision), history_test.go (5 cases covering perms
on new and existing files, on-disk truncation, blank-input, newline
flattening), provider_test.go (provider switching + picker transitions
+ SLM gating).
vikingowl
e38cce5f1f