refactor: extract SearchResultItem and SearchResultsList from SearchContent (#124)

* design: search subtitle metadata layout with 2 frames

Frame 1: Search result items with metadata subtitle line showing
modified date, word count, and link count below the snippet.
Frame 2: NoteList items with enhanced subtitle including link count.

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

* feat: add metadata subtitle to search results and note list items

- formatSubtitle now shows link count (e.g. "2h ago · 342 words · 5 links")
- New formatSearchSubtitle shows full metadata in search results:
  modified date, created date, word count, and link count
- SearchPanel renders metadata line under each search result snippet
- Mock entries updated with realistic outgoingLinks data
- 11 new tests covering formatSearchSubtitle and search result metadata

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

* refactor: extract SearchResultItem and SearchResultsList from SearchContent

Reduces cyclomatic complexity from 24 to manageable levels by
splitting the monolithic SearchContent into three focused components.
Code Health: 8.97 -> 9.23.

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

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

src/utils/noteListHelpers.test.ts

@@ -1,5 +1,5 @@
 import { describe, it, expect, vi, afterEach } from 'vitest'
-import { formatSubtitle, relativeDate } from './noteListHelpers'
+import { formatSubtitle, formatSearchSubtitle, relativeDate } from './noteListHelpers'
 import type { VaultEntry } from '../types'
 
 function makeEntry(overrides: Partial<VaultEntry> = {}): VaultEntry {
@@ -48,6 +48,80 @@ describe('formatSubtitle', () => {
     expect(result).toContain('50 words')
     expect(result).toContain('\u00b7')
   })
+
+  it('includes link count when outgoingLinks is non-empty', () => {
+    const entry = makeEntry({ modifiedAt: 1700000000, wordCount: 200, outgoingLinks: ['a', 'b', 'c'] })
+    const result = formatSubtitle(entry)
+    expect(result).toContain('3 links')
+  })
+
+  it('uses singular "link" when exactly one', () => {
+    const entry = makeEntry({ wordCount: 100, outgoingLinks: ['one'] })
+    expect(formatSubtitle(entry)).toContain('1 link')
+    expect(formatSubtitle(entry)).not.toContain('1 links')
+  })
+
+  it('omits link count when outgoingLinks is empty', () => {
+    const entry = makeEntry({ modifiedAt: 1700000000, wordCount: 50, outgoingLinks: [] })
+    expect(formatSubtitle(entry)).not.toContain('link')
+  })
+
+  it('formats word count with locale separators for large numbers', () => {
+    const entry = makeEntry({ wordCount: 1240 })
+    const result = formatSubtitle(entry)
+    expect(result).toMatch(/1,?240 words/)
+  })
+})
+
+describe('formatSearchSubtitle', () => {
+  afterEach(() => { vi.restoreAllMocks() })
+
+  it('shows modified date, created date, word count, and links', () => {
+    const now = Math.floor(Date.now() / 1000)
+    const entry = makeEntry({
+      modifiedAt: now - 3600,
+      createdAt: now - 86400 * 30,
+      wordCount: 520,
+      outgoingLinks: ['a', 'b', 'c', 'd', 'e'],
+    })
+    const result = formatSearchSubtitle(entry)
+    expect(result).toContain('1h ago')
+    expect(result).toContain('Created')
+    expect(result).toContain('520 words')
+    expect(result).toContain('5 links')
+  })
+
+  it('omits created date when same as modified', () => {
+    const now = Math.floor(Date.now() / 1000)
+    const entry = makeEntry({ modifiedAt: now, createdAt: now, wordCount: 100 })
+    const result = formatSearchSubtitle(entry)
+    expect(result).not.toContain('Created')
+  })
+
+  it('omits created date when createdAt is null', () => {
+    const now = Math.floor(Date.now() / 1000)
+    const entry = makeEntry({ modifiedAt: now, createdAt: null, wordCount: 100 })
+    const result = formatSearchSubtitle(entry)
+    expect(result).not.toContain('Created')
+  })
+
+  it('shows "Empty" for zero word count', () => {
+    const entry = makeEntry({ modifiedAt: 1700000000, wordCount: 0 })
+    expect(formatSearchSubtitle(entry)).toContain('Empty')
+  })
+
+  it('omits link count when no outgoing links', () => {
+    const entry = makeEntry({ modifiedAt: 1700000000, wordCount: 50, outgoingLinks: [] })
+    expect(formatSearchSubtitle(entry)).not.toContain('link')
+  })
+
+  it('falls back to createdAt when modifiedAt is null', () => {
+    const entry = makeEntry({ createdAt: 1700000000, wordCount: 200, outgoingLinks: ['a'] })
+    const result = formatSearchSubtitle(entry)
+    expect(result).toContain('200 words')
+    expect(result).toContain('1 link')
+    expect(result).not.toContain('Created')
+  })
 })
 
 describe('relativeDate', () => {