v0.7.4

Summary

Introduces an Antigravity/Gemini-style compact thinking UI with live one-liner step summaries and collapsible dropdowns, native zero-dependency EPUB book extraction, sub-millisecond cache fast-paths and offline chat management, dynamic per-turn BM25 grounding in interactive Q&A, calibrated single-pass token chunking, and deterministic release CI builds.

Changes

• Compact Thinking UI (src/engine/llm.rs, src/ui/render.rs): Replaced multi-line raw thinking trace dumps with a live, real-time one-liner spinner summary (💭 Thinking: <Step> (Xs)...) and an Antigravity/Gemini-style collapsible dropdown indicator (💭 Thought for Xs ›), preserving the full chain-of-thought in HTML reader views and opt-in --show-thinking CLI streaming.
• Native EPUB Ingestion (src/sources/epub.rs, src/sources/document.rs): Pure-Rust zero-dependency EPUB book extraction and chapter stitching in reading order using existing zip and XML dependencies.
• Cache Fast-Paths & Offline Chat (src/main.rs, src/commands/ask.rs): Instantaneous sub-millisecond cache hit delivery for web, books, and local files before initializing network or LLM engines, complete reasoning trace preservation, and offline chat management (--chats, --show-chat, --delete-chat).
• Dynamic BM25 Grounding & Index Filtering (src/commands/ask.rs, src/storage/db.rs): Re-ranks grounding context dynamically per turn in interactive Q&A, optimizes single-pass BM25 chunk scoring, and filters stop words and short tokens in the library search index to prevent table bloat.
• Engine & Streaming Fixes (src/engine/llm.rs, src/ui/printer.rs): Calibrated single-pass tokenization ratios eliminating N+1 /tokenize loops, aligned tree reduction tokens with active profiles, and preserved line buffering in StreamMarkdownRenderer when color is disabled.
• Security Hardening (src/storage/db.rs, src/sources/youtube.rs): Sanitized YAML frontmatter scalars and filename collisions in Markdown vault exports, validated SQL attachment identifiers, and hardened YouTube transcript parsing against malformed escapes.
• Build & CI Pipeline (.github/workflows/release.yml): Streamlined release workflow using rust-cache for deterministic, reliable release artifact generation.