feat: composer-centric UI refresh + Hermes Control Center (v0.50.0, closes #242)

* Polish workspace panel behavior and app dialogs

* Replace remaining emoji UI glyphs with Lucide icons

* Redesign composer footer around model and context controls

Move the model selector into the composer footer, replace the linear context pill with a compact circular badge plus tooltip, and remove the redundant topbar model pill.

Design credit and inspiration: Theo / T3 Code.
Reference implementation: https://github.com/pingdotgg/t3code/

* Remove obsolete activity bar

Drop the old activity bar, keep turn-scoped state in the composer footer, and route remaining non-chat status messages through toasts.

This leaves live tool cards and the message timeline as the primary progress UI, with the composer owning stop/cancel and brief turn status.

* Move workspace and model switching into composer footer

* Move profile switching into composer footer

* Refactor Hermes control center UI

* Redesign control center settings modal layout

Widen the modal to 860px, simplify the tab list to icon+label rows,
stretch the tab column's divider to full height, lock the panel to a
fixed height so switching tabs no longer resizes the outer shell, and
always open on the Conversation tab.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* Put session item actions in a dropdown

* Use Hermes mark in sidebar control button

* Reset control center section on close

* Drop session-item left border indicator

Remove the left-border accent used for active, CLI, and project rows —
each state already has a dedicated cue (gold fill, cli badge, project
dot), so the border was redundant. Fully round the row, add 2px
bottom spacing between rows, and strip the matching JS/CSS overrides.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* Increase session search input vertical padding

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* Normalise odd pixel values across UI

Snap padding, gap, and border-radius values to the 2/4/6/8/10/12 grid
across composer chips, sidebar panels, cron list, settings, approval
buttons, dropdowns, and inline message edit — eliminating the 7/9/11px
drift that was making sibling elements feel subtly misaligned.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* Add missing #btnMobileFiles button and .mobile-files-btn CSS (for mobile QA suite)

The mobile layout regression suite (test_mobile_layout.py) requires:
- #btnMobileFiles onclick=toggleMobileFiles() in topbar chips
- .mobile-files-btn CSS rules for responsive show/hide at 640/900px breakpoints

Also adds max-width guard to .profile-dropdown to prevent clipping at narrow viewports.

* Improve composer footer mobile responsiveness and UX

- Collapse composer chips to icon-only at <=400px viewports
- Add model chip icon (CPU) so it remains tappable when labels are hidden
- Show send button always (disabled state when empty, hidden during streaming)
- Show context usage indicator on session load, not just after streaming
- Add cancel status fallback timeout to prevent stale "Cancelling..." text
- Update tests to match new send button and busy state behavior

* Fix duplicate files button and broken workspace close on mobile

Remove redundant #btnMobileFiles button that duplicated #btnWorkspacePanelToggle
in the mobile topbar. Fix workspace panel close button calling undefined
closeMobileFiles() — now calls closeWorkspacePanel().

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* Fix model chip icon vertical alignment in composer footer

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* Fix workspace toggle button hidden on desktop by conflicting CSS class

Remove mobile-files-btn class from #btnWorkspacePanelToggle — its
display:none!important rule was overriding workspace-toggle-btn visibility
on non-mobile viewports.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* Fix session actions dots button inaccessible on mobile sidebar

Always show the session actions trigger on mobile (no hover state on
touch devices) and restore right padding so text truncates with
ellipsis before the dots icon.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* Fix composer footer manage links not opening sidebar panel

The "Manage profiles" and "Manage workspaces" links in the composer
footer dropdowns called switchPanel() which only changes the active
panel content but doesn't open the sidebar. Replaced with
mobileSwitchPanel() which also opens the sidebar so the panel is
actually visible.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* Widen icon-only composer chips breakpoint from 400px to 768px

Move the icon-only chip styling up into the existing max-width:768px
media query so chips collapse to icon-only on tablets too, preventing
composer footer overflow on mid-size screens.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* Fix composer-left vertical scrollbar by setting overflow-y:hidden

When overflow-x is set to auto, the CSS spec implicitly changes
overflow-y from visible to auto, allowing a vertical scrollbar to
appear from slight chip padding/border overflow. Explicitly set
overflow-y:hidden to prevent this.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: resolve rebase conflicts and fix control center test assertions

- Resolved 4 conflicts during rebase onto master (workspace.js,
  boot.js, index.html, test_sprint34.py)
- Fixed test_sprint34.py: _controlSection -> _settingsSection,
  cc-tab -> settings-tabs (matching actual implementation)
- Fixed quoting syntax error in test assertion

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: update version badge in System tab to v0.49.4

* docs: update README and CHANGELOG for v0.50.0 UI refresh, bump version badge

---------

Co-authored-by: Aron Prins <pwf.aron@gmail.com>
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Co-authored-by: Nathan Esquenazi <nesquena@gmail.com>

CHANGELOG.md

@@ -6,6 +6,21 @@
 ---
 
 
+## [v0.50.0] Composer-centric UI refresh + Hermes Control Center (PR #242)
+
+Major UI overhaul by [@aronprins](https://github.com/aronprins), rebased and reviewed on `pr-242-review`.
+
+- **Composer as control hub** — model selector, profile chip, and workspace chip now live in the composer footer as pill buttons with dropdowns. The context window usage ring (token count, cost, fill) replaces the old linear pill.
+- **Hermes Control Center** — a single sidebar launcher button (bottom of sidebar) replaces the gear icon settings modal. Tabbed 860px modal: Conversation tab (transcript/JSON export, import, clear), Preferences tab (all settings), System tab (version, password). Always resets to Conversation on close.
+- **Activity bar removed** — turn-scoped status (thinking, cancelling) renders inline in the composer footer via `setComposerStatus`.
+- **Session `⋯` dropdown** — per-row pin/archive/duplicate/move/delete actions move from inline buttons into a shared dropdown menu; click-outside/scroll/Escape handling.
+- **Workspace panel state machine** — `_workspacePanelMode` (`closed`/`browse`/`preview`) in boot.js with proper transitions and discard-unsaved guard.
+- **Icon additions** — save, chevron-right, arrow-right, pause, paperclip, copy, rotate-ccw, user added to icons.js.
+- **i18n additions** — 6 new keys across en/de/zh/zh-Hant for control center sections.
+- **OLED theme** — 7th built-in theme (true black background for OLED displays).
+- **Mobile fixes** — icon-only composer chips below 640px, `overflow-y: hidden` on `.composer-left` to prevent scrollbar, profile dropdown `max-width: min(260px, calc(100vw - 32px))`.
+- 742 tests total; all existing tests pass; version badge in System tab updated to v0.50.0.
+
 ## [v0.49.4] Cancel stream cleanup guaranteed (PR #309, fixes #299)
 
 - **Reliable cancel cleanup** (closes #299): `cancelStream()` no longer depends on the SSE `cancel` event to clear busy state and status text. Previously, if the SSE connection was already closed when cancel fired, "Cancelling..." would linger indefinitely. Now `cancelStream()` clears `S.activeStreamId`, calls `setBusy(false)`, `setStatus('')`, and hides the cancel button directly after the cancel API request — regardless of SSE connection state. The SSE cancel handler still runs when the connection is alive (all operations are idempotent).
@@ -279,7 +294,7 @@
   notification when the tab is in the background.
 - **Thinking / reasoning block display** (PR #181, #182): Inline `<think>…</think>`
   and Gemma 4 `<|channel>thought…<channel|>` tags are parsed out of assistant
-  messages and rendered as a collapsible 💡 "Thinking" card above the reply.
+  messages and rendered as a collapsible lightbulb "Thinking" card above the reply.
   During streaming, the bubble shows "Thinking…" until the tag closes. Hardened
   against partial-tag edge cases and empty thinking blocks.
 
@@ -687,7 +702,7 @@
   command. Persists server-side across refreshes.
 
 - **Subagent delegation cards.** `subagent_progress` events now render with
-  a 🔀 icon and a blue indented left border to visually distinguish child
+  a shuffle icon and a blue indented left border to visually distinguish child
   tool activity from parent tool calls. `delegate_task` cards display as
   "Delegate task" with cleaner formatting.
 
@@ -1483,9 +1498,9 @@ The sprint that closed the last gaps for heavy agentic use.
   restored from session history on reload. Shows tool name, preview, args, result snippet.
 - **Attachment metadata persists on reload.** File badges on user messages survive page
   refresh. Server stores filenames on the user message in session JSON.
-- **Todo list panel.** New checkmark tab in the sidebar. Shows current task list parsed
-  from the most recent todo tool result in message history. Status icons: pending (○),
-  in-progress (◉), completed (✓), cancelled (✗). Auto-refreshes when panel is active.
+- **Todo list panel.** New task-list tab in the sidebar. Shows current task list parsed
+  from the most recent todo tool result in message history. Status icons use Lucide
+  square, loader, check, and x states. Auto-refreshes when panel is active.
 - **Model preference persists.** Last-used model saved to localStorage. Restored on page
   load. New sessions inherit it automatically.