feat(tui): pluggable busy-indicator styles (#13610) (#17150)

* feat(tui): pluggable busy-indicator styles (kaomoji/emoji/unicode/ascii)

The status-bar `FaceTicker` rotated through wide-and-variable kaomoji
glyphs (`(｡•́︿•̀｡)`, `( ͡° ͜ʖ ͡°)`, …) every 2.5s.  Real display widths range
from ~5 to ~16 columns, so the rest of the bar (cwd, ctx %, voice,
bg counter) shifted on every cycle.  Padding the verb alone (#17116)
helped but didn't address the dominant jitter source — the glyph
itself.

Add four indicator styles, configurable + hot-swappable:

* `kaomoji` (default — preserves the existing vibe; verb is now
  pad-stable so the only width churn left is the kaomoji itself).
* `emoji`  — single 2-col emoji frame (`⚕ 🌀 🤔 ✨ 🍵 🔮`).
* `unicode` — `unicode-animations` braille spinner (1-col, smooth).
* `ascii`  — `| / - \` (1-col, max compat).

Wires:

* `display.tui_status_indicator` in `DEFAULT_CONFIG` (default
  `kaomoji`).
* New JSON-RPC `config.set/get indicator` keys, narrow allow-list.
* `applyDisplay` reads the field and patches `UiState.indicatorStyle`,
  so the existing `mtime` poll picks up `~/.hermes/config.yaml` edits
  within ~5s without a TUI restart.
* `/indicator [style]` slash command (alias `/indicator-style`,
  subcommand completion `kaomoji|emoji|unicode|ascii`).  Bare form
  shows the current style; setter fires `config.set` and
  optimistically `patchUiState({ indicatorStyle })` so the live TUI
  swaps immediately, matching the `/skin` UX.
* `CommandDef("indicator", ..., subcommands=...)` so classic CLI
  autocomplete + TUI `complete.slash` both surface it.
* `FaceTicker` decouples spinner cadence from verb cadence — the
  glyph runs at the spinner's authored interval (or `FACE_TICK_MS`
  for kaomoji), the verb stays on the original 2.5s cycle, and both
  re-arm cleanly when style changes.

Tests:

* `normalizeIndicatorStyle` rejects unknown / non-string input.
* `applyDisplay → tui_status_indicator` covers fan-out + fallback.
* `/indicator <style>` hot-swaps `UiState.indicatorStyle` after a
  successful `config.set`.
* `/indicator sparkle` rejects with the usage hint and never hits
  the gateway.
* Slash-parity matrix gets `'/indicator'` → `config.get`.

Validation:
  cd ui-tui && npm run type-check — clean; npm test --run — 398/398.
  scripts/run_tests.sh tests/test_tui_gateway_server.py
  tests/hermes_cli/test_commands.py — 220/220.

* chore(tui): drop /indicator-style alias to declutter autocomplete

* fix(tui): drop verb-width pad — /indicator handles glyph jitter directly

* fix(tui): unicode indicator style hides the verb (cleanest option)

* refactor(tui): single source of truth for INDICATOR_STYLES; cleaner error format

Round 1 Copilot review on PR #17150:

- Exported `INDICATOR_STYLES` const tuple from `interfaces.ts`;
  `IndicatorStyle` union type is derived from it. `useConfigSync`
  builds its validation Set from the tuple, and `session.ts` uses it
  for both the usage hint and the runtime allow-list — adding/removing
  a style now touches one line.
- Backend `config.set indicator` error message: switched
  `sorted(allowed)` list repr to `pick one of ascii|emoji|kaomoji|unicode`
  (matches the TUI usage hint), and reports the normalized `raw`
  instead of the original `value`. Backend allowed tuple now has a
  comment pointing back at `INDICATOR_STYLES` so the two stay aligned.

Note: kept the verb portion unpadded per design intent — fixed-width
padding was the exact UX the `/indicator` command was added to remove.
Stable width comes from the glyph; verbs cycling is part of the kawaii
aesthetic. Reply on the verb thread will explain.

* fix(tui): drop type collapse + gate verb timer + DEFAULT_INDICATOR_STYLE

Round 2 Copilot review on PR #17150:

- `tui_status_indicator?: 'ascii' | ... | string` collapses to `string`
  in TS — consumers got no narrowing. Documented as plain `string` with
  a comment about runtime validation via `normalizeIndicatorStyle`.
- `FaceTicker` always started a 2.5s verb interval, even for the
  `unicode` style which hides the verb entirely. Now gated on
  `showVerb` from `renderIndicator` — `unicode` stays calm.

Pre-emptive self-review (avoid round 3):
- Three call sites duplicated the literal `'kaomoji'` default
  (uiStore, normalizeIndicatorStyle, slash command). Added
  `DEFAULT_INDICATOR_STYLE` to interfaces.ts and threaded it through
  so changing the default touches one line.

* fix(tui-gateway): normalize config.get indicator output to match TUI render

Round 4 Copilot review on PR #17150: `config.get` for `indicator`
returned the raw `display.tui_status_indicator` value without
validation, so a hand-edited config.yaml with stray casing or an
unknown style would leave `/indicator` printing one thing while
the TUI rendered the kaomoji default (frontend's
`normalizeIndicatorStyle` does this normalization on receive).

Lifted the allow-list to module scope as `_INDICATOR_STYLES` /
`_INDICATOR_DEFAULT`, reused by both `config.set` and `config.get`.
Comment notes the alignment with `INDICATOR_STYLES` /
`DEFAULT_INDICATOR_STYLE` in interfaces.ts so adding/removing a
style is a one-line change on each end.

Tests cover: known value verbatim, casing/whitespace normalize,
unknown→default, unset→default.

* fix(tui-gateway): preserve falsy-input diagnostics in config.set indicator error

Round 5 Copilot review on PR #17150: `raw = str(value or "").strip().lower()`
collapsed any falsy non-string (`0`, `False`, `[]`) to empty string,
so the error message read `unknown indicator: ` with nothing after —
losing the original input.

Switched to `("" if value is None else str(value)).strip().lower()`
so only `None` (the genuine 'no value' case) becomes blank.  Used
`{raw!r}` in the error so the diagnostic is unambiguous (`'0'` vs `0`).

Tests:
- known-value happy path (`'EMOJI'` → `'emoji'`)
- falsy non-string inputs (`0` / `False` / `[]`) surface meaningfully
- `None` keeps the blank-repr error

hermes_cli/config.py

@@ -715,6 +715,9 @@ DEFAULT_CONFIG = {
         "inline_diffs": True,     # Show inline diff previews for write actions (write_file, patch, skill_manage)
         "show_cost": False,       # Show $ cost in the status bar (off by default)
         "skin": "default",
+        # TUI busy indicator style: kaomoji (default), emoji, unicode (braille
+        # spinner), or ascii.  Live-swappable via `/indicator <style>`.
+        "tui_status_indicator": "kaomoji",
         "user_message_preview": {  # CLI: how many submitted user-message lines to echo back in scrollback
             "first_lines": 2,
             "last_lines": 2,