Bug 1 (CRITICAL): canonicalCount >= 1 always fired on first <promise> tag
(prompt echo). Changed to >= 2 so only 2nd+ occurrence triggers completion.
Bug 2: checkMultiLinePatterns() re-detected complete tags already handled
by processLine(), double-counting. Now only tries completion when partial
buffer is non-empty (cross-chunk scenario).
Bug 3: TodoWrite ✔ patterns required "Task #N" but real Claude Code output
is plain "✔ content". Added TODO_PLAIN_CHECKMARK_PATTERN fallback.
Includes 71 new deep tests + real-life verification.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
