Migrate to dwm-flexipatch

Enables preprocessor-based patch management with the following patches:

Functionality:
- dwmblocks: Clickable status bar integration
- cool_autostart: Runs dwmblocks on startup
- cyclelayouts: Cycle through layouts
- pertag: Per-tag layouts/nmaster/mfact
- restartsig: Restart dwm in place
- scratchpads: Multiple scratchpads (spterm, spcalc)
- shiftview/shifttag: Navigate and move between tags
- stacker: Stack management (focusstack/pushstack)
- sticky: Sticky windows across all tags
- swallow: Terminal window swallowing
- togglefullscreen: Toggle fullscreen
- vanitygaps: Configurable gaps
- xresources: Runtime color configuration
- cfacts: Resize clients in stack

Layouts:
- tile, monocle, bstack
- centeredmaster, centeredfloatingmaster
- deck, spiral, dwindle

Custom settings:
- Border: 3px, red selection (#770000)
- Gaps: 20h/10v inner, 10h/30v outer
- Font: monospace:size=11 + NotoColorEmoji
- Autostart: dwmblocks
- Scratchpads: spterm, spcalc