feat: v0.6.0 light mode, command palette, dialogs, toasts

- Light mode with the house ☀/◐ toggle and lt_theme preference; light
  terminal palette; Claude runs with dark-ansi so its colours follow the
  palette; tmux and the statusLine use ANSI colours.
- Command palette (⌕, Ctrl+Shift+P) with session, terminal, view, link and
  help commands.
- .lt-modal dialogs for new/rename/end and a keyboard shortcuts sheet.
- .lt-toast results for actions, uploads, copy and CI.
- ttyd dropped the reply of fast one-shot commands; replies now wait for the
  browser to hang up, and the client hangs up as soon as it has one.
- Sessions panel re-fetches after an action instead of reusing a stale poll.

Closes #31
Closes #32
Closes #33
Closes #34
Closes #35

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

README.md

@@ -46,6 +46,7 @@ The tmux server runs in its own unit, so every Claude process lives in **that**
   - Configure `DEVDESK_GRAFANA_URL`, plus a Viewer token in `DEVDESK_GRAFANA_TOKEN_FILE`.
 - **Repo / CI panel:** branch, ahead/behind, uncommitted changes, HEAD's Gitea CI status and open PRs for the session's folder. When CI fails, **Ask Claude to fix CI** types a prompt to read the failed job's log.
 - **Context:** a Claude `statusLine` command (`devdesk-statusline`) snapshots each session's model, context-window use and cost to `/var/lib/devdesk/context/<session>.json`. The Sessions panel shows it as a bar (cost in the tooltip), and Claude's own footer shows a one-line summary.
+- **Light mode:** the terminal switches palettes with the page. DevDesk starts Claude with its `dark-ansi` theme so Claude draws with the terminal's 16 colours, and the light palette maps bright white to ink; tmux and the status line use ANSI colours too. A session picks up Claude's theme the next time Claude starts in it (`/exit`, then ⏎ resumes the same conversation).
 - **Phone:** a key bar replaces the shortcut hints (Esc, Tab, ⇧Tab, ^C, ↑, ↓, ⏎, Claude/Shell window), and the panels open as a drawer.
 - **SSH:** `devdesk attach <name>`, `devdesk new <name> [project]`, `devdesk rename <old> <new>`, `devdesk end <name>`, `devdesk ls`, `devdesk pick`, `devdesk repo <name>`, `devdesk alerts`.
 
@@ -59,8 +60,9 @@ The tmux server runs in its own unit, so every Claude process lives in **that**
 | Ctrl-b d | Detach (the session keeps running) |
 | Shift+drag | Native browser selection (plain drag goes to tmux copy-mode, which copies via OSC 52) |
 | Ctrl+Shift+C / V | Copy selection / paste |
+| Ctrl+Shift+P | Command palette (also the ⌕ button) |
 
-Text size, desktop notifications (with a mute) and fullscreen are in the **⋯** menu. In Chromium, fullscreen also captures Ctrl+W/Ctrl+T, which browsers otherwise keep for themselves.
+The **☀/◐** button switches light and dark mode (saved per browser, shared with the other web_template apps' `lt_theme` preference). Text size, desktop notifications (with a mute), the keyboard shortcuts sheet and fullscreen are in the **⋯** menu; everything is also in the command palette. In Chromium, fullscreen also captures Ctrl+W/Ctrl+T, which browsers otherwise keep for themselves.
 
 ## Configuration
 - **Put your changes in `/etc/devdesk/env.local`.** It's read after the packaged `env` and never shipped, so `apt upgrade` never asks about it. Example: `DEVDESK_REMOTE_CONTROL=1`.