[Misc] Stylizing Before Release

[fedonman]

Refreshed the visual theme and tightened keybindings ahead of the first release. Every widget now has its own accent color when focused — cyan for the script viewer, green for stdout, red for stderr, purple for custom panels, and orange for the filter sidebar — and focused borders switched from rounded to double so the active panel is immediately obvious. Marked job rows use an inverted style (dark text on a colored background) instead of the old underline, the cursor symbol changed from a filled circle to a triangle, and the base palette was nudged darker overall. Several single-key shortcuts that conflicted with text input were moved behind Ctrl: widget selector is now Ctrl+W, column config is Ctrl+C, select-all is Ctrl+A, cancel is Ctrl+X, and reset is Ctrl+R in both the field and filter dialogs; the same treatment was applied to the add (Ctrl+A) and delete (Ctrl+D) actions in the widget selector. The layout engine was reworked so the right column holds up to three widgets and any overflow spills into the left column below the table on an aligned grid, replacing the earlier scheme that squeezed up to four panels on the right and tacked extras onto a half-height bottom strip; the total visible panel cap is now five (2×3−1) to guarantee the table always keeps at least one grid row. Widget titles were simplified by dropping the job ID suffix, and the "Execution Script" label was shortened to "Script". The README was rewritten with a full keybinding reference split by context, an updated architecture tree, and expanded feature descriptions.