docs: UI-audit fixes in CLAUDE.md, API, OpenAPI, LANES and READMEs

New params and errors (agents session_ids, sessions awaiting/from/to,
stats tool counts, event labels, cleanup dry_run/INVALID_PURGE_DAYS, lane
start slot auto/ESESSIONLIVE/EUNSUPPORTED), terminal and pane shortcuts,
the shared UI primitives, accent vs accent-solid, lazy routes and the
Settings groups. openapi.yaml regenerated.

client/README.md

@@ -58,7 +58,8 @@ The client is a single-page application (SPA) built with modern web technologies
 
   Other rules that fall out of this:
   - **Light mode's hue family is warm, dark mode's is cool.** The light ramp is Claude's own ivory/terracotta (`#e8e5da` → `#fcfbf7`, warm neutrals, warm `--shadow-card`), not Radix slate: a cool near-white page reads as glare at any lightness, because the brightest thing on screen is also the bluest. Dark mode stays slate + blue — a warm accent on a near-black page is a different problem with a different answer.
-  - Light `--accent` is **not** the dark one, in hue or in step. Dark's `#0090ff` is 3.3:1 on white; Claude's brand terracotta `#cc785c` is 3.1:1 on ivory and 3.3:1 under white text, so it works as a large fill and fails as a link or a button label. Light mode uses it two steps down, `#a34a28` — 5.3:1 as text on a card, 5.9:1 white-on-accent.
+  - Light `--accent` is **not** the dark one, in hue or in step. Dark's `#0090ff` is 3.3:1 on white; Claude's brand terracotta `#cc785c` is 3.1:1 on ivory and 3.3:1 under white text, so it works as a large fill and fails as a link or a button label. Light mode uses it three steps down, `#924224` (it was `#a34a28`, which missed 4.5:1 as text on its own selected chip).
+  - **White text sits on `accent-solid`, never on `accent`.** `--accent` is a TEXT colour; in the dark themes it is the light step (Default `#70b8ff`, Orca Dark `#6aa0f8`) that reads on a near-black card and is far too light to carry white. Every theme also defines `--accent-solid`/`--accent-solid-hover` (Tailwind `bg-accent-solid`) for the fill behind white text — `.btn-primary`, a Switch's on state, a Checkbox tick — darkened until white clears 4.5:1 (Default `#0076d1`). In the light themes the text accent is already dark enough, so `--accent-solid` is simply `var(--accent)`.
   - `--fg-muted` carries real content (timestamps, counts), so it is held at ≥4.5:1 (`#686359`, 5.4:1 on a card), not at the decorative value the Radix step suggests.
   - Code colouring goes through the `syntax.*` tokens (`--syn-*`), never fixed Tailwind steps: the dark set is pastel (300-level), the light set is the same hues four steps darker, because a pastel keyword on a light code block is unreadable.
   - Anything that assumes a dark background — a hardcoded near-black panel, `hover:text-white`, `filter: invert(1)` on a form control glyph — is a light-mode bug. Use tokens, or scope the rule under `.dark`.
@@ -518,6 +519,8 @@ function App() {
 }
 ```
 
+The heavy pages — `Workspace` (xterm, the diff viewer), `SettingsHub` and `SessionDetail` — are `React.lazy` imports in `App.tsx`, each route wrapped in `<Suspense>` (the `Page` helper), so they load on first visit instead of in the initial bundle. `App.tsx` also mounts the app-wide `<Toaster />` and `<ConfirmHost />` once, beside `<GlobalTooltip />`.
+
 ### Navigation Flow
 
 ```mermaid
@@ -627,6 +630,8 @@ graph TB
     style Success fill:#10B981
 ```
 
+A thrown error carries the server's `error.code` as `code` and the HTTP `status` (plus `runId` from a `409 ESESSIONLIVE` start, `auth` from `409 EGITAUTH`). A `200` that is not JSON — the SPA's `index.html` from a proxy or a dev server that missed the route — throws `code: "EBADRESPONSE"` with the translated `errors:badResponse` message instead of `Unexpected token '<'`. Pages surface a failure through `toast` (`lib/toast.ts`, rendered by `components/Toaster.tsx`; an error toast stays until dismissed) rather than `alert()`, and ask for confirmation through `confirmDialog`/`confirmDiscard` (`lib/confirm.ts`, rendered by `components/ConfirmHost.tsx`) rather than `window.confirm`.
+
 ---
 
 ## UI Components