feat: 117 bundled IR maps + rule viewer + authority pages

## Major improvements

### 117 maps now live-demoable (was 10)
Generated IR for top maps across every authority + script pair.
117 of 287 maps now transliterate live in the browser; the rest
link to GitHub source.

### Rule viewer (RuleViewer.vue)
- New component on every bundled-map detail page
- Shows first 20 rules in a readable table
- Columns: # | type (sub/parallel/run/funcall) | pattern → replacement | context
- Color-coded kind badges (ochre=run, saffron=parallel, green=funcall)
- Links to GitHub for the full .imp source

### Per-authority landing pages (/authorities/[slug])
- 35 pages generated, one per authority
- Each shows: full name, system count, with-tests count, source/dest
  scripts, year range, languages covered
- Full system list with year, name, code, script flow, test vector
- Full-name lookup table for 35 known authorities
- Back-link to /authorities index

### Authorities index redesigned
- Real counts derived from catalogue (not hardcoded)
- 34 authorities listed with system counts and links
- Total summary: 'N authorities, M systems'

### MapCatalogue enhancements
- 'Live-demoable in browser' filter checkbox
- LIVE badge on cards that have bundled IR
- liveDemoable boolean passed from page (detected via readdirSync)

### interscript-ts parity breakthrough
- Fixed lookaround bug: before/after now use (?<=...) / (?=...) instead
  of capture groups
- Tamil (தமிழ் → tamil̮) NOW MATCHES RUBY EXACTLY
- 4/5 sample maps byte-exact (was 3/5)

## Build
340 pages total (was 305): +35 authority detail pages

## Tests (79 vitest, was 68)
- test/authorities.test.ts: 11 new tests for authority pages
- Existing 68 tests unchanged

Author: ronaldtse