Build NovelCompass UI replacement for Novel Updates

[cbangera2]

What changed

• adds a Manifest V3 Chrome extension that replaces supported Novel Updates pages with the NovelCompass interface while preserving a reversible Original View
• covers series pages, finder/search, rankings, homepage/catalog routes, recommendation lists, reading lists, public profiles, and shared navigation/account state
• adds a toolbar popup for enablement, light/dark/system theme, and default-view preferences
• aligns the popup and route replacements with the NovelCompass violet/lavender palette
• preserves authenticated or mutation-heavy Novel Updates controls behind safe native-view transitions
• adds route adapters, sanitization contracts, runtime storage migration, fixtures, and UI/content-script tests

Why

Novel Updates has valuable data and authenticated functionality, but its route-specific UI is inconsistent with the NovelCompass experience. This extension supplies a coherent NovelCompass presentation without attempting to replace Novel Updates as the source of truth.

Validation

• extension test suite: 165 passing
• full extension TypeScript/build pipeline passing
• Manifest V3 package validator passing
• pre-push web typecheck passing
• Python suite: 53 passing
• live Chrome route checks performed for replacement/original-view behavior, popup settings, and account-aware pages

Follow-up in this PR

• finish final live Chrome verification against the rebuilt unpacked directory
• document and implement a lightweight package boundary so large ranking/search datasets are downloaded and cached on demand rather than shipped in the initial extension

[cbangera2]

Lightweight delivery follow-up is now included in this PR.

• Core install: 155.4 KiB ZIP / 513.3 KiB unpacked / 0 bundled dataset bytes
• One extension and one repository; rankings continue parsing Novel Updates live
• Enhanced Finder/Similar data is explicitly enabled from the popup and fetched as versioned, integrity-checked shards
• Publisher creates 2,037 immutable search/identity/facet/recommendation/detail artifacts; largest is below the 2 MiB broker ceiling
• Existing GitHub Pages workflow publishes the artifacts after merge
• Compact client path never downloads legacy catalog.json
• Extension tests: 181/181 passing; Python tests: 56/56 passing
• Live Chrome QA passed for popup permission denial/allow error states, Reading List, profiles, light/dark theme, and zero extension errors

The existing Pages endpoint will return 404 until this branch is merged and the Pages workflow publishes the new extension-data/v1 tree; that pre-publication state is handled gracefully by the popup and does not affect core NU restyling.