doc: update inferInstanceAs docstring and rename normalizeInstance to wrapInstance (#13115)

This PR updates the `inferInstanceAs` docstring to reflect current
behavior: it requires an
expected type from context and should not be used as a simple
`inferInstance` synonym. The
old example (`#check inferInstanceAs (Inhabited Nat)`) no longer works,
so it's replaced
with one demonstrating the intended transport use case.

Additionally, renames `InstanceNormalForm.lean` to `WrapInstance.lean`,
`normalizeInstance`
to `wrapInstance`, and the trace class `Meta.instanceNormalForm` to
`Meta.wrapInstance`,
removing the "instance normal form" terminology from both documentation
and code.

Context:
https://leanprover.zulipchat.com/#narrow/channel/270676-lean4/topic/inferInstanceAs.20is.20broken/near/581449313

🤖 Prepared with Claude Code

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.github/workflows/ci.yml

@@ -76,9 +76,20 @@ jobs:
               fi
               echo "nightly=$LEAN_VERSION_STRING" >> "$GITHUB_OUTPUT"
             else
-              # Scheduled: do nothing if commit already has a different tag
+              # Scheduled: do nothing if commit already has a different tag (e.g. a release tag)
               LEAN_VERSION_STRING="nightly-$(date -u +%F)"
-              if [[ "$(git name-rev --name-only --tags --no-undefined HEAD 2> /dev/null || echo "$LEAN_VERSION_STRING")" == "$LEAN_VERSION_STRING" ]]; then
+              HEAD_TAG="$(git name-rev --name-only --tags --no-undefined HEAD 2> /dev/null || true)"
+              if [[ -n "$HEAD_TAG" && "$HEAD_TAG" != "$LEAN_VERSION_STRING" ]]; then
+                echo "HEAD already tagged as ${HEAD_TAG}, skipping nightly"
+              elif git rev-parse "refs/tags/${LEAN_VERSION_STRING}" >/dev/null 2>&1; then
+                # Today's nightly already exists (e.g. from a manual release), create a revision
+                REV=1
+                while git rev-parse "refs/tags/${LEAN_VERSION_STRING}-rev${REV}" >/dev/null 2>&1; do
+                  REV=$((REV + 1))
+                done
+                LEAN_VERSION_STRING="${LEAN_VERSION_STRING}-rev${REV}"
+                echo "nightly=$LEAN_VERSION_STRING" >> "$GITHUB_OUTPUT"
+              else
                 echo "nightly=$LEAN_VERSION_STRING" >> "$GITHUB_OUTPUT"
               fi
             fi