Pages no longer park on a compile that was refused mid-read

When a node type reuses code from a neighbouring node, the compiler has to go and fetch that neighbour. That fetch was being made on the compiler's behalf without an identity attached — the platform quite correctly refuses an unattributed read, and the refusal came back looking exactly like "the neighbour does not exist". The reference was then left in the code as written, so the compile failed on the reference line itself and the node type parked with an error. Every page served by that type waited on the parked type before giving up.

A compile reading the source it was asked to compile is platform work, not something done on any one person's behalf, so those reads now run under the platform's own identity — the same way the compiler already discovers which files belong to a type. The same change applies to the compiler's second route for finding source files, which could previously see a smaller set of files than the first and report missing types that were in fact present.