feat: add project infrastructure and rewrite README

Problem: nonicons.nvim lacks CI, pre-commit hooks, nix dev shell, issue
templates, and the README contains content that duplicates the vimdoc.

Solution: add quality/luarocks CI workflows, pre-commit config, nix
flake, prettier config, GitHub issue/discussion templates, and rewrite
the README to minimal style with all detailed content in vimdoc. Update
yamatsum/nonicons references to ya2s/nonicons.

.github/DISCUSSION_TEMPLATE/q-a.yaml

@@ -0,0 +1,17 @@
+title: 'Q&A'
+labels: []
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Use this space for questions, ideas, and general discussion about nonicons.nvim.
+        For bug reports, please [open an issue](https://github.com/barrettruth/nonicons.nvim/issues/new/choose) instead.
+  - type: textarea
+    attributes:
+      label: Question or topic
+    validations:
+      required: true
+  - type: textarea
+    attributes:
+      label: Context
+      description: Any relevant details (Neovim version, config, screenshots)

.github/ISSUE_TEMPLATE/bug_report.yaml

@@ -0,0 +1,78 @@
+name: Bug Report
+description: Report a bug
+title: 'bug: '
+labels: [bug]
+body:
+  - type: checkboxes
+    attributes:
+      label: Prerequisites
+      options:
+        - label:
+            I have searched [existing
+            issues](https://github.com/barrettruth/nonicons.nvim/issues)
+          required: true
+        - label: I have updated to the latest version
+          required: true
+
+  - type: textarea
+    attributes:
+      label: 'Neovim version'
+      description: 'Output of `nvim --version`'
+      render: text
+    validations:
+      required: true
+
+  - type: input
+    attributes:
+      label: 'Operating system'
+      placeholder: 'e.g. Arch Linux, macOS 15, Ubuntu 24.04'
+    validations:
+      required: true
+
+  - type: textarea
+    attributes:
+      label: Description
+      description: What happened? What did you expect?
+    validations:
+      required: true
+
+  - type: textarea
+    attributes:
+      label: Steps to reproduce
+      description: Minimal steps to trigger the bug
+      value: |
+        1.
+        2.
+        3.
+    validations:
+      required: true
+
+  - type: textarea
+    attributes:
+      label: 'Health check'
+      description: 'Output of `:checkhealth nonicons`'
+      render: text
+
+  - type: textarea
+    attributes:
+      label: Minimal reproduction
+      description: |
+        Save the script below as `repro.lua`, edit if needed, and run:
+        ```
+        nvim -u repro.lua
+        ```
+        Confirm the bug reproduces with this config before submitting.
+      render: lua
+      value: |
+        vim.env.LAZY_STDPATH = '.repro'
+        load(vim.fn.system('curl -s https://raw.githubusercontent.com/folke/lazy.nvim/main/bootstrap.lua'))()
+        require('lazy.nvim').setup({
+          spec = {
+            {
+              'barrettruth/nonicons.nvim',
+              dependencies = { 'nvim-tree/nvim-web-devicons' },
+            },
+          },
+        })
+    validations:
+      required: true

.github/ISSUE_TEMPLATE/config.yaml

@@ -0,0 +1,5 @@
+blank_issues_enabled: false
+contact_links:
+  - name: Questions
+    url: https://github.com/barrettruth/nonicons.nvim/discussions
+    about: Ask questions and discuss ideas

.github/ISSUE_TEMPLATE/feature_request.yaml

@@ -0,0 +1,30 @@
+name: Feature Request
+description: Suggest a feature
+title: 'feat: '
+labels: [enhancement]
+body:
+  - type: checkboxes
+    attributes:
+      label: Prerequisites
+      options:
+        - label:
+            I have searched [existing
+            issues](https://github.com/barrettruth/nonicons.nvim/issues)
+          required: true
+
+  - type: textarea
+    attributes:
+      label: Problem
+      description: What problem does this solve?
+    validations:
+      required: true
+
+  - type: textarea
+    attributes:
+      label: Proposed solution
+    validations:
+      required: true
+
+  - type: textarea
+    attributes:
+      label: Alternatives considered

.github/workflows/luarocks.yaml

@@ -0,0 +1,21 @@
+name: luarocks
+
+on:
+  push:
+    tags:
+      - 'v*'
+
+jobs:
+  quality:
+    uses: ./.github/workflows/quality.yaml
+
+  publish:
+    needs: quality
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: nvim-neorocks/luarocks-tag-release@v7
+        env:
+          LUAROCKS_API_KEY: ${{ secrets.LUAROCKS_API_KEY }}

.github/workflows/quality.yaml

@@ -0,0 +1,89 @@
+name: quality
+
+on:
+  workflow_call:
+  pull_request:
+    branches: [main]
+  push:
+    branches: [main]
+
+jobs:
+  changes:
+    runs-on: ubuntu-latest
+    outputs:
+      lua: ${{ steps.changes.outputs.lua }}
+      markdown: ${{ steps.changes.outputs.markdown }}
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dorny/paths-filter@v3
+        id: changes
+        with:
+          filters: |
+            lua:
+              - 'lua/**'
+              - 'plugin/**'
+              - '*.lua'
+              - '.luarc.json'
+              - '*.toml'
+            markdown:
+              - '*.md'
+
+  lua-format:
+    name: Lua Format Check
+    runs-on: ubuntu-latest
+    needs: changes
+    if: ${{ needs.changes.outputs.lua == 'true' }}
+    steps:
+      - uses: actions/checkout@v4
+      - uses: JohnnyMorganz/stylua-action@v4
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
+          version: 2.1.0
+          args: --check .
+
+  lua-lint:
+    name: Lua Lint Check
+    runs-on: ubuntu-latest
+    needs: changes
+    if: ${{ needs.changes.outputs.lua == 'true' }}
+    steps:
+      - uses: actions/checkout@v4
+      - name: Lint with Selene
+        uses: NTBBloodbath/selene-action@v1.0.0
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
+          args: --display-style quiet .
+
+  lua-typecheck:
+    name: Lua Type Check
+    runs-on: ubuntu-latest
+    needs: changes
+    if: ${{ needs.changes.outputs.lua == 'true' }}
+    steps:
+      - uses: actions/checkout@v4
+      - name: Run Lua LS Type Check
+        uses: mrcjkb/lua-typecheck-action@v0
+        with:
+          checklevel: Warning
+          directories: lua
+          configpath: .luarc.json
+
+  markdown-format:
+    name: Markdown Format Check
+    runs-on: ubuntu-latest
+    needs: changes
+    if: ${{ needs.changes.outputs.markdown == 'true' }}
+    steps:
+      - uses: actions/checkout@v4
+      - name: Setup pnpm
+        uses: pnpm/action-setup@v4
+        with:
+          version: 8
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+      - name: Install prettier
+        run: pnpm add -g prettier@3.1.0
+      - name: Check markdown formatting with prettier
+        run: prettier --check .