add snonux static microblog generator

Full Go implementation with:
- txt/md/image/audio input processing, URL auto-linking in .txt files
- Paginated HTML output with Atom feed
- 11 visual themes: neon, terminal, synthwave, minimal, brutalist, paper,
  aurora, matrix, ocean, retro, glass (selectable via --theme flag)
- Keyboard navigation (j/k/arrows, Enter modal, h/l page nav)
- Shared nav templates (navhints, navmodal, navscript) across all themes
- Magefile build automation; integration test suite covering all themes

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

1 files changed, 100 insertions, 0 deletions

diff --git a/internal/generator/shared.go b/internal/generator/shared.go
new file mode 100644
index 0000000..eed4de3
--- /dev/null
+++ b/internal/generator/shared.go
@@ -0,0 +1,100 @@
+package generator
+
+// navDefs is appended to every theme template when parsing.
+// It defines three named sub-templates shared across all themes:
+//   - "navhints"  — keyboard shortcut hint bar HTML
+//   - "navmodal"  — full-screen expanded-post modal HTML
+//   - "navscript" — keyboard navigation JavaScript
+//
+// Each theme calls {{template "navhints" .}}, {{template "navmodal" .}}, and
+// {{template "navscript" .}} at the appropriate points in its HTML.
+// All CSS for these elements (colours, borders, backdrop) lives in each theme
+// so themes remain self-contained and independently styled.
+const navDefs = `
+{{define "navhints"}}
+<div class="nav-hints" aria-label="keyboard shortcuts">
+    <span><kbd>j</kbd><kbd>k</kbd> or <kbd>↑</kbd><kbd>↓</kbd> select post</span>
+    <span><kbd>Enter</kbd> expand</span>
+    <span><kbd>Esc</kbd> close</span>
+    <span><kbd>h</kbd><kbd>l</kbd> or <kbd>←</kbd><kbd>→</kbd> change page</span>
+</div>
+{{end}}
+
+{{define "navmodal"}}
+<div class="post-modal" id="post-modal">
+    <div class="modal-inner">
+        <button class="modal-close" onclick="closeModal()">[ ESC ] CLOSE</button>
+        <div id="modal-content"></div>
+    </div>
+</div>
+{{end}}
+
+{{define "navscript"}}
+<script>
+    // === KEYBOARD NAVIGATION ===
+    // j / ArrowDown  → next post       k / ArrowUp    → previous post
+    // h / ArrowLeft  → previous page   l / ArrowRight → next page
+    // Enter          → expand modal    Esc            → close modal
+    const posts = document.querySelectorAll('.post');
+    let currentIndex = posts.length > 0 ? 0 : -1;
+    const prevPageURL = {{.PrevPageJSON}};
+    const nextPageURL = {{.NextPageJSON}};
+
+    if (currentIndex >= 0) selectPost(0);
+
+    function selectPost(index) {
+        if (posts.length === 0) return;
+        if (currentIndex >= 0) posts[currentIndex].classList.remove('post-active');
+        currentIndex = Math.max(0, Math.min(index, posts.length - 1));
+        posts[currentIndex].classList.add('post-active');
+        posts[currentIndex].scrollIntoView({ behavior: 'smooth', block: 'nearest' });
+        playNavSound();
+    }
+
+    // playNavSound generates a short beep via the Web Audio API.
+    // A fresh AudioContext per call avoids state issues across navigations.
+    function playNavSound() {
+        try {
+            const ctx = new (window.AudioContext || window.webkitAudioContext)();
+            const osc = ctx.createOscillator();
+            const gain = ctx.createGain();
+            osc.connect(gain); gain.connect(ctx.destination);
+            osc.frequency.value = 220; osc.type = 'sine';
+            gain.gain.setValueAtTime(0.15, ctx.currentTime);
+            gain.gain.exponentialRampToValueAtTime(0.001, ctx.currentTime + 0.08);
+            osc.start(ctx.currentTime); osc.stop(ctx.currentTime + 0.08);
+        } catch (_) {}
+    }
+
+    function openModal() {
+        if (currentIndex < 0) return;
+        document.getElementById('modal-content').innerHTML =
+            posts[currentIndex].querySelector('.post-text').innerHTML;
+        document.getElementById('post-modal').classList.add('active');
+    }
+
+    function closeModal() {
+        document.getElementById('post-modal').classList.remove('active');
+    }
+
+    document.addEventListener('keydown', function(e) {
+        if (e.target.tagName === 'INPUT' || e.target.tagName === 'TEXTAREA') return;
+        if (document.getElementById('post-modal').classList.contains('active')) {
+            if (e.key === 'Escape') { closeModal(); e.preventDefault(); }
+            return;
+        }
+        switch (e.key) {
+            case 'j': case 'ArrowDown':  selectPost(currentIndex + 1); e.preventDefault(); break;
+            case 'k': case 'ArrowUp':    selectPost(currentIndex - 1); e.preventDefault(); break;
+            case 'h': case 'ArrowLeft':
+                if (prevPageURL) { playNavSound(); window.location.href = prevPageURL; }
+                e.preventDefault(); break;
+            case 'l': case 'ArrowRight':
+                if (nextPageURL) { playNavSound(); window.location.href = nextPageURL; }
+                e.preventDefault(); break;
+            case 'Enter': openModal(); e.preventDefault(); break;
+        }
+    });
+</script>
+{{end}}
+`