feat(theme): add warm burnout theme

[octjelau]

Quick port of https://github.com/felipefdl/warm-burnout/tree/main/tmux

[psmux]

Hey @octjelau, thank you for the port, warm burnout is a great, understated addition to the theme collection.

Here is what I actually checked before merging.

Colors: I pulled the upstream warm-burnout-dark.conf and warm-burnout-light.conf straight from felipefdl/warm-burnout and diffed every hex code against your plugin.conf and .ps1 palette tables. Every value matches exactly, base #14120f, text #b4a89c, accent #ff8f40, session #ffb454, active border #b8522e, message #1f1d17, mode #f5c56e for dark, and the corresponding light set. This is a faithful port, not an approximation.

Separators: our repo recently fixed a window tab powerline orientation bug across the other eight themes (issue #58, commits d739e7d and bdb50bc). I checked whether that convention applied here and it does not, because the upstream warm-burnout theme itself never uses powerline glyphs at all, it is intentionally plain text with an empty window-status-separator. Your port correctly mirrors that, so there was nothing to fix.

Structure: compared your plugin.conf, README, and .ps1 entry point against psmux-theme-tokyonight for convention, everything lines up, including the @warm-burnout-variant option pattern and the README.md index entry.

Live test: on an isolated psmux -L reviewtest server I loaded your plugin.conf via source-file exactly the way PPM would apply it, then ran show-options -g and confirmed status-style, status-left, status-right, pane-active-border-style, message-style, mode-style, window-status-format and window-status-current-format all came through with your exact colors and no errors. I also ran it three times back to back to rule out flakiness, all three came up clean.

One heads up for later, unrelated to your PR, tests/test_all_plugins.ps1 reads themes from the locally installed ~/.psmux/plugins folder rather than the repo checkout, so it only exercises whatever happens to be installed there. Not something you need to touch.

Merged as e0aa30b. Looking forward to more of these.