fix(search): snippet always fills the full context window

scripts/smoke.mjs

@@ -154,4 +154,23 @@ check('search matches an author name', () => {
   assert.ok(hits[0].matched.includes('nirodbaran'));
 });
 
+check('snippet fills the full context window when the matched term is near the start', () => {
+  // term at position 0; text is much longer than the default contextChars (120)
+  const body = 'equanimity ' + 'x '.repeat(65); // ~141 chars, term at idx 0
+  const s = snippet({ body }, ['equanimity']);
+  const bare = s.replace(/ …$/, '');
+  // With the fix: window is [0, 120]. Without it: window was only [0, 60].
+  assert.ok(bare.length >= 110, `expected ≥110 chars, got ${bare.length}`);
+});
+
+check('snippet fills the full context window when the matched term is near the end', () => {
+  // term near the end; text is longer than contextChars (120)
+  const prefix = 'x '.repeat(65); // 130 chars
+  const body = prefix + 'equanimity'; // 140 chars, term at idx 130
+  const s = snippet({ body }, ['equanimity']);
+  const bare = s.replace(/^… /, '');
+  // With the fix: window slides back to cover ~120 chars. Without it: only ~70 chars.
+  assert.ok(bare.length >= 110, `expected ≥110 chars, got ${bare.length}`);
+});
+
 console.log(`\n${passed} checks passed.`);

src/search.js

@@ -127,8 +127,10 @@ export function snippet(article, terms = [], { contextChars = 120 } = {}) {
       if (at !== -1 && (idx === -1 || at < idx)) idx = at;
     }
     if (idx === -1) continue;
-    const start = Math.max(0, idx - half);
-    const end = Math.min(text.length, idx + half);
+    // Slide the window so it always spans contextChars when the text is long
+    // enough, rather than halving when the match is near the start or end.
+    const start = Math.max(0, Math.min(idx - half, text.length - contextChars));
+    const end = Math.min(text.length, start + contextChars);
     let s = text.slice(start, end).trim();
     if (start > 0) s = `… ${s}`;
     if (end < text.length) s = `${s} …`;