feat(kb): split-view PDF jump-to-page for both ask and search modes

Search and ask modes now render results as a two-column layout: a left
column with ranked hit cards (search) or Shira's answer + source picker
(ask), and a right column with an iframe showing the source PDF scrolled
to page_number. Clicking a hit (search) or source pill (ask) swaps the
iframe's src, so users can verify a quote against the original PDF
without leaving the KB tab.

- search: renderSearchResults lays out results as panel cards on the
  left (with kind + title + section + "עמ׳ N" label); the top hit is
  pre-selected and its PDF loads on the right. Clicking any card
  re-highlights it and swaps the preview. Law-kind hits (Wikisource
  text) gracefully fall back to a chunk-text panel with a Wikisource
  link so the right pane never 404s on a text source.
- ask: renderAskAnswer dedups /kb/ask's sources[] by source_id,
  collects all cited pages per source, and renders a picker row plus
  per-source page-jump buttons. First source's first page loads on
  initial render; buttons swap the iframe without re-running the query.

Depends on shira-hermes commits e534709 + 1ca1cc0 (chunker page_number
propagation + null-byte strip) — without them, every PDF collapses to
page 1 in the DB and the jump links are cosmetic.

Refs Task Master #1

.gitignore

@@ -1,2 +1,27 @@
 *.zip
 .DS_Store
+
+# Logs
+logs
+*.log
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+dev-debug.log
+# Dependency directories
+node_modules/
+# Environment variables
+.env
+# Editor directories and files
+.idea
+.vscode
+*.suo
+*.ntvs*
+*.njsproj
+*.sln
+*.sw?
+# OS specific
+
+# Task files
+# tasks.json
+# tasks/