PHLEGM v7 baseline recovery checkpoint

- Emulator/runtime source is based on the last-good PHLEGM v6 build from 2026-1004-2002-0000.
- The broken 2026-1005 MC6809/dual-CPU runtime rewrite is intentionally not forward-ported in this recovery checkpoint.
- Canonical micro-code engine filename is src/lib/microcode.lib, using the known-good engine implementation.
- Every explicit machine/chipset selection clears and recompiles the execution image; SESSION-LOAD now always recompiles from current *.phlegm definitions before restoring mutable state.
- Current Oct. 5 compiler/bootstrap handoff logic is retained.
- The authoritative current three external bootstrap scripts are preserved byte-for-byte and mirrored under tools/bootstrap/.
- Unknown-duration compiler progress is restored to the known-good two-piece mapping: raw 0..97% -> visible 0..30%, raw 97..100% -> visible 30..100%, with 99.9% running ceiling.
- Active build/package metadata and filenames are advanced to PHLEGM v7.
