Three fixes for Iverson's dfn
{1≥≢⍵:⍵ ⋄ p←⍵⌷⍨?≢⍵ ⋄ (∇⍵⌿⍨⍵<p),(p=⍵)/⍵,∇⍵⌿⍨⍵>p}:
1. parser: standalone op-glyph branch (/ ⌿ \ ⍀) now consumes a
following ⍨ or ¨ and emits :derived-fn — `⍵⌿⍨⍵<p` parses
as compress-commute (was previously dropping ⍨)
2. tokenizer: `name←...` (no spaces) now tokenizes as separate
:name + :assign instead of eating ← into the name. ⎕← still
stays one token for the output op
3. inline p←⍵⌷⍨?≢⍵ mid-dfn now works via existing :assign-expr
Full suite 585/585. Phase 10 complete (all 7 items ticked).
Remaining gaps for a future phase: heterogeneous-strand inner
product is the only unfinished part — life works after dropping ⊃,
quicksort works directly.