Custom Markdown Snippets Not Loading in LuaSnip

[adimail]

After adding custom Markdown snippets in the ~/.config/nvim/lua/snippets/markdown.lua file and configuring LuaSnip, the snippets are not recognized in .md files. I have ensured filetype detection works and keybindings for snippet expansion are set up. However, the snippets remain inaccessible when editing Markdown files.

snippets/markdown.md

lua/snippets/markdown.md
local ls = require('luasnip')
local s = ls.snippet
local t = ls.text_node
local i = ls.insert_node
local f = ls.function_node

return {
    -- Headings
    s('h1', { t('# '), i(1, 'Header 1') }),
    s('h2', { t('## '), i(1, 'Header 2') }),
    ...
    ...
    ...
}

Other extensions are working fine, but the markdown snippets are not working.

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for more reference, here is my nvim config.