Direct port of ~/repos/opencode/packages/opencode/src/tool/edit.ts: the
9-stage replacer chain (Simple, LineTrimmed, BlockAnchor, WhitespaceNormalized,
IndentationFlexible, EscapeNormalized, TrimmedBoundary, ContextAware,
MultiOccurrence), Levenshtein-based block-anchor similarity, and the
disproportionate-match guard that hard-stops rather than falling through to
the next candidate. Also ports edit.test.ts's scenarios: new-file creation,
BOM preservation, CRLF handling, replaceAll, directory/not-found/identical
errors, loose block-anchor rejection, and concurrent edits to the same file
serializing through a per-path tokio::Mutex without losing either change.
99 tests passing across the workspace, clippy clean. This lands the last
of the six M1 built-in tools (read/write/edit/bash/glob/grep).
Erik Simon
bfb2dca7de