v0.3.0

What's New

RandomAccessChunker interface

• New RandomAccessChunker interface for O(1) chunk retrieval by range label
• Built-in chunkers (LineChunk, MarkdownChunker, BracketChunker, IndentChunker) use lazy line-offset tables
• ChunkCache dispatches to the fast path when available, falls back to streaming
• Breaking: ChunkTexter interface removed — replaced by RandomAccessChunker

FileChunker interface split

• FileChunker is now a separate interface (FileChunks method) for binary formats that read files directly
• A single type can implement both Chunker and FileChunker
• Overlay (tmp://) requires Chunker; FileChunker-only chunkers error on tmp:// paths

Markdown headline merging

• Heading chunks now absorb following tag-only chunks (lines starting with @) and one content chunk
• Internal blank lines between merged sections are included in the chunk content
• Produces richer heading contexts for downstream consumers (e.g. ark search)

Other changes

• ContentLen field in C records — chunk byte length without re-reading files
• ChunkContentLens(fileid) method for per-file chunk size statistics
• TmpFileInfo for overlay document metadata
• Overlay chunk-level UTF-8 validation