chore(adr): reserve numbers 045-049 in INDEX (#89)

Cherry-pick ADR numbers 045-049 on main so concurrent branches don't collide.

- 045: Processing Provenance Signals (PR #60, was missing from index)
- 046: Component Examples
- 047: Slot Content
- 048: PropConfigurations PropBinding
- 049: Nested Slot Compositions (deferred recursion follow-on to 047)

ADR files for 045 live in PR #60; files for 046-049 are drafted on the
`042-composition-type` branch. This commit only registers the numbers
in INDEX.md; no ADR files are added.

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: nathanacurtis

adr/INDEX.md

@@ -4,7 +4,12 @@
 
 | # | Title | Highlights |
 |---|-------|------------|
-| 044 | Duplicate Layer Name Disambiguation | |
+| 049 | Nested Slot Compositions | Recursion follow-on to ADR-047: fill nested instances' slots from a parent context (reserved, draft on `042-composition-type` branch) |
+| 048 | PropConfigurations PropBinding | Widen `PropConfigurations` value union to add `PropBinding` (reserved, draft on `042-composition-type` branch) |
+| 047 | Slot Content — Component.slotContent and SlotBinding | Add `Component.slotContent: Record<string, Composition>` + `SlotBinding` extending `PropBinding` with `$extensions['com.figma'].default` (reserved, draft on `042-composition-type` branch) |
+| 046 | Component Examples — InstanceExample and Component.examples | Add `InstanceExample` and `ComponentExamples`; add `Component.examples?` named record (reserved, draft on `042-composition-type` branch) |
+| 045 | Processing Provenance Signals | (reserved, draft in PR #60) |
+| 044 | Duplicate Layer Name Disambiguation | (reserved, draft in PR #60) |
 | 043 | Custom Color Format Configuration | |
 | 042 | Composition as a First-Class Type | |
 | 041 | Layout Positioning — Constraint-Based Naming | |