Op Create Dialog improvement and Index ordering

[function-store]

Family Tab Ordering

The Index parameter is absolute — it refers to a slot in the full OP Create
tab bar, which includes TD's built-in family tabs (COMP, TOP, CHOP, SOP, MAT, DAT).

Example

Assume TD has 6 built-in families at slots 0–5:

0	1	2	3	4	5
COMP	TOP	CHOP	SOP	MAT	DAT

You install 4 custom families:

Family	Index
MyFX	7
MyGen	-1
MyIO	-1
MyUtil	-1

Result:

0	1	2	3	4	5	6	7	8	9
COMP	TOP	CHOP	SOP	MAT	DAT	MyGen	MyFX	MyIO	MyUtil

• The three -1 families are wildcards. They fill the first available slots after
  all built-ins (starting at 6), skipping slot 7 which is claimed by MyFX.
• MyFX at Index=7 is pinned within the wildcard group — one wildcard before it,
  two after.

Rules

• Explicit index: the family lands at that absolute slot. Multiple families
  sharing the same index are sorted alphabetically, all appearing before the
  built-in at that slot (if any).
• Index = -1: auto-assigned. Wildcard families fill the first available slots
  after all built-ins, alphabetically, skipping any slot claimed by an
  explicit-index family.

Previous behavior (before this fix)

All Index=-1 families were assigned a sort position of 999999, meaning they
all raced to the very end. An explicit-index family like MyFX with Index=7
ended up first among custom families — because 7 < 999999 — even though the
intent was for it to sit in the middle of the group.

With the same 4 families the result was:

6	7	8	9
MyFX	MyGen	MyIO	MyUtil

MyFX was placed before any wildcard family regardless of its requested slot,
making explicit ordering within the custom group impossible.