Content-Anchored Text Edits

DC-12 supports deterministic arbitrary-span EditText generation and replay for existing text-file nodes. A modified text file is represented as one enclosing span selected by byte LCP/LCS and widened to UTF-8 character boundaries. The record remains the FDD-03 node-addressed, span-anchored EditText shape; no offsets or new identity fields are added.

Author text edits from worktree changes with:

prikk commit --from-worktree --text-edits -m "record text changes"

--text-edits is retained for compatibility. Existing-node kind is authoritative, so text-file modifications author EditText and binary-file modifications author ReplaceBinary.

Generation and replay remain conservative:

• Only modified tracked files are candidates.
• Both baseline and current bytes must be valid UTF-8.
• Text edits use a single deterministic enclosing span; multi-operation diff minimization is deferred.
• Byte-level differences that split a multibyte character are widened to the enclosing UTF-8 character.
• Binary or invalid UTF-8 modifications fail closed for text nodes; they do not become ReplaceBinary.
• Replay localizes by old_span_text, left/right anchor hashes, and span_id, then splices exactly.

This deliberately avoids byte offsets and line offsets. Presentation offsets may be derived later, but they are not part of patch identity or replay preconditions.

Current validation rules:

• old_span_hash is exactly 32 bytes.
• old_span_hash must equal text_span_hash(old_span_text).
• old_span_text and replacement_text must be well-formed UTF-8.
• The target node_id must name a live TextFile during replay.

Deferred work:

• multi-operation text diff minimization
• direct inverse and rollback extension for arbitrary spans
• commutation and conflict witnesses