arduino-cli compiles now read libraries from a per-compile --libraries dir of
symlinks materialized by the pro overlay (owner store -> cache -> legacy), via
the existing materialize_library_scope hook, instead of scanning the shared
mutable global volume. --libraries only overrides the USER library search path,
so cores + board-manager URLs (RP2040 earlephilhower, ATTinyCore) are untouched.
Mirrors the ESP-IDF P2.1e graceful fallback: an incomplete manifest (a needed or
transitive lib not declared) makes the scoped compile miss a header; we retry
ONCE scan-all (no --libraries) and surface manifest_incomplete, so a partial
manifest degrades to legacy behavior instead of hard-failing.
Dedup correctness: the manifest + owner are resolved ONCE (shared
_resolve_compile_scope) and folded into the /compile/start dedup key AND threaded
into the build, so two owners with identical sketch+board but different custom
libs never coalesce to one another's job, and the key never diverges from the
bytes the build uses. Owner folded only when a manifest applies (index-only
compiles keep cross-owner dedup).
2ee443470d