feat: interactive Spec Text view in Phoenix Inspect
New "Spec" mode in the pipeline visualizer. Shows the actual spec
text with line numbers. Lines mapping to clauses have a blue left
border. Click any line to trace the full path:
Spec text → Clause → Canonical Nodes → IUs → Generated Files
Right panel shows the trace with color-coded canonical types
(REQUIREMENT=blue, CONSTRAINT=red, INVARIANT=purple), risk tiers,
file sizes, and drift status.
Also: phoenix ingest now shows clause diffs before overwriting,
and includes the raw spec file content in inspect data for the
text view.