Adds a new, independent fence (ha_state_t.upgrade_materialization_fence)
distinct from the existing config-byte serve-fence: that fence tracks
whether the locally-held config bytes hash-match the committed marker;
this one tracks whether THIS MEMBER'S OWN upgrade-snapshot
materialization (task 5's marker-triggered checkpoint) has actually
completed for the current committed marker, with the live on-disk
config bytes still hash-verifying against it right now.
upgrade_materialization_verify(c) mirrors config_activate_committed's
shape: reads the current committed marker, checks whether
persist.cfgref_present/cfgref_tag/cfgref_sha already reflect it (stamped
by every checkpoint via scan_latest_committed_config_ref -- proof this
member's own materialization ran for this exact marker), and separately
re-reads the LIVE on-disk config bytes fresh on every call (never a
cached/embedded copy) to hash-verify them too. Both must hold for the
fence to clear. Logs loud only on the 0->1 transition, never
exits/aborts, always fail-loud + fence + stay alive + retriable.
upgrade_materialization_fenced(c) is the trivial atomic-read accessor.
Not yet wired into the dispatch gate, promotion gate, or an automatic
retry trigger -- that's task 6.2. Task 6.1 of 19.
Requirements: 1.8, 3.2, 3.4
Rongsong Shen
7b507156a0