design-md-consolidation 2.1: delete Decision 7 (Term::If REVERTED block)

docs/DESIGN.md

@@ -590,38 +590,6 @@ server, LSP) was deferred — all three layer additively on the
 static-prompt path ships, which remains the
 lowest-common-denominator fallback that always works.
 
-## Decision 7: redundancy removal — `Term::If` is not a primitive
-
-This decision was made on shaky grounds —
-applying CLAUDE.md's "no redundancies" rule to a case that turned out to
-be primitive control flow, not redundancy. The post-removal match-on-Bool
-form (3× the tokens, asymmetric `pat-wild` for the false case) was
-worse for token economy and worse for the natural shape of the language.
-`Term::If` is restored. The text below is preserved for the audit trail.
-
-`Term::If { cond, then, else_ }` is semantically a subset of
-`Term::Match` on `Bool`. Per CLAUDE.md the language must contain no
-redundancies; two AST nodes for the same operation produces an
-authoring decision with no semantic content and an extra codegen
-path. `Term::If` was removed. Migration shape on the JSON side:
-
-  {"t":"if","cond":C,"then":A,"else":B}
-    →
-  {"t":"match","scrutinee":C,
-    "arms":[
-      {"pat":{"p":"lit","lit":{"kind":"bool","value":true}},"body":A},
-      {"pat":{"p":"wild"},"body":B}]}
-
-The wildcard arm satisfies the typechecker's
-`primitive-needs-wildcard` rule. A future iter may upgrade the
-exhaustiveness check to recognise the `true`+`false` arm pair as
-covering Bool without a wildcard; until then, wildcard is the
-canonical migration target.
-
-No schema version bump (no third-party consumes `ailang/v0`).
-Hash invalidation for the three migrated fixtures (`sum`, `sort`,
-`max3`) is intentional; the new hashes become the new identity.
-
 ## Decision 8: explicit, verified tail calls
 
 For an LLM author, recursion is the natural iteration form