Three-part fix for the library-contamination class of ESP32 compile
failures (a user's project kept pulling unrelated libraries because 79%
of projects compile with an empty manifest, forcing scan-all resolution
over ~1000 shared libraries):
1. Name-affinity ranking in _find_library_for_header: the provider whose
name matches the header stem wins (exact normalized match > esp32
arch declaration > contains-stem, alphabetical only as tie-break).
Previously first-alphabetical won, so any stray library shipping a
generic header (Servo.h has 6 providers) could hijack the build.
2. Manifest auto-migration: scan-all compiles now report the libraries
the build really used (manifest_incomplete +
manifest_suggested_libraries on the compile result); the editor folds
single-candidate suggestions into the board's declared manifest after
a green build, so the NEXT compile runs scoped. One green build = one
migrated project; empty-manifest scan-all behaviour is untouched.
3. Install-declares: the Wokwi import library modal records successful
installs in the active board's manifest, and .vlx export/import now
round-trips board.libraries.
Tests: test_espidf_library_ranking.py (9) + library-manifest.test.ts (19).