Theorem v1.3.0

Added

• Theorem Lens (In-Place Footnote & Citation Peek Portals) — Tapping footnotes,
  citations, <aside> blocks, and bibliographic references now displays a dynamic,
  anchored popover balloon right above or below the link. Allows reading notes,
  inspecting formulas, and copying text without losing reading position or jumping
  to the back of the book.
• Companion Audiobook & Immersion Integration Plan — Added full architectural
  specification and GitHub issue template for attaching DRM-free .m4b/.mp3 audio tracks
  to books with native variable-speed playback, sleep timers, and Iroh P2P sync.
• Comprehensive Project Documentation & Strategy — Added docs/discover.md,
  docs/COMPETITIVE_STRATEGY_BLUEPRINT.md, and synchronized all feature guides with
  the latest codebase implementation.

Fixed & Performance

• PDF Navigation Synchronization & Smooth Scroll — Resolved previous-page
  navigation stalls in continuous scroll mode by deferring DOM scrolling until target
  page wrappers are mounted, and pre-loading adjacent pages (page - 1, page + 1)
  in single-page mode for instantaneous (0ms) page transitions.
• PDF Single-Page Auto-Fit & Centering — Switched to m-auto layout on page wrappers
  to prevent CSS flex clipping and automatically applied page-fit zoom when switching
  to single-page presentation mode.
• PDF Engine Memory Reclamation & Disposal — Ensured loadingTask.destroy() is
  invoked on document unmount, deallocated canvas pixel buffers (width = 0; height = 0;),
  cleared text layers, and triggered sqliteShrinkMemory() on reader close.
• PDF Presentation Mode Persistence — Added presentationMode (scroll vs paged)
  to PdfViewState in SQLite and Zod sync schemas, persisting per-book display settings.
• Universal Route Error Boundary Layout — Standardized error handling layout and
  typography across all app views.