♻️ Restructure: Move Astro to repository root

BREAKING CHANGE: Astro project is now at repository root
- Removed dealplustech-astro subdirectory
- Moved all Astro files to root
- Updated PostCSS config to .cjs
- Removed old Next.js files

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✅ Ready for Easypanel deployment (no root dir needed)

Migration path:
- Old structure: /dealplustech-astro/
- New structure: / (root)

dealplustech-astro/node_modules/prismjs/components/prism-mizar.min.js

@@ -1 +0,0 @@
-Prism.languages.mizar={comment:/::.+/,keyword:/@proof\b|\b(?:according|aggregate|all|and|antonym|are|as|associativity|assume|asymmetry|attr|be|begin|being|by|canceled|case|cases|clusters?|coherence|commutativity|compatibility|connectedness|consider|consistency|constructors|contradiction|correctness|def|deffunc|define|definitions?|defpred|do|does|end|environ|equals|ex|exactly|existence|for|from|func|given|hence|hereby|holds|idempotence|identity|iff?|implies|involutiveness|irreflexivity|is|it|let|means|mode|non|not|notations?|now|of|or|otherwise|over|per|pred|prefix|projectivity|proof|provided|qua|reconsider|redefine|reduce|reducibility|reflexivity|registrations?|requirements|reserve|sch|schemes?|section|selector|set|sethood|st|struct|such|suppose|symmetry|synonym|take|that|the|then|theorems?|thesis|thus|to|transitivity|uniqueness|vocabular(?:ies|y)|when|where|with|wrt)\b/,parameter:{pattern:/\$(?:10|\d)/,alias:"variable"},variable:/\b\w+(?=:)/,number:/(?:\b|-)\d+\b/,operator:/\.\.\.|->|&|\.?=/,punctuation:/\(#|#\)|[,:;\[\](){}]/};