fix(typescript): map included .ts files in step output

Two adjacent blocks in container.js merge a transpile mapping after
compiling TypeScript. The helper block merges into store.tsFileMapping;
the include/support block merges only into container.tsFileMapping.

Step.line() reads store.tsFileMapping, so a step whose stack frame points
into an included page object had no entry to match and was printed with
the deleted .temp.mjs sibling instead of the .ts source. Error stacks were
unaffected because fixErrorStack() is handed the mapping directly.

The include block now merges into store as well, mirroring the helper
block two hundred lines above it.

Closes #5675

Author: luantaraschi

lib/container.js

@@ -892,6 +892,16 @@ async function loadSupportObject(modulePath, supportObjectName) {
           for (const [key, value] of mapping.entries()) {
             container.tsFileMapping.set(key, value)
           }
+          // Step.line() maps temp paths back through store, not through the
+          // container, so an include has to land there too. Without this a step
+          // that originates in an included .ts page object is printed with the
+          // deleted .temp.mjs sibling. (#5675)
+          if (!store.tsFileMapping) {
+            store.tsFileMapping = new Map()
+          }
+          for (const [key, value] of mapping.entries()) {
+            store.tsFileMapping.set(key, value)
+          }
         } catch (tsError) {
           throw new Error(`Failed to load TypeScript file ${importPath}: ${tsError.message}. Make sure 'typescript' package is installed.`)
         }