godaudits 2.15.0: closing the system-design mirror

Closes the mirror against godplans 1.12.0. That release added R-ARCH-21
through R-ARCH-24 to the plan-time architecture module: read consistency and
partition key per entity group, redundancy topology behind each availability
number, cache tiering with a staleness budget, and an overload posture per
entry surface. 2.14.0 had already covered caching, backpressure, recovery
objectives, and scale-out readiness from the audit side, so two obligations
were left with nothing checking them: what a read is allowed to see, and
whether an availability target has any redundancy standing behind it.

Two checks, 435 to 437. Both are audit-only and both are zero-weight routing
checks, so a repo's architecture score moves only through the dimension the
finding implicates, never through a new bucket. No scoring dimension changed
weight, so a 2.14.0 audit re-run under 2.15.0 scores the same unless one of the
two new checks fires.

Added

• A-ARCH-28 (audit-only, deep-trace, conditional on read replicas or a
  partitioned store) checks that read consistency was decided rather than
  inherited: replica-served paths tolerate the staleness they get, post-write
  reads on money, auth, and inventory resolve to the primary, and a table
  projected past single-node scale carries a partition key instead of an open
  growth curve. A balance or post-write confirmation served from a replica with
  no recorded staleness tolerance is High. Partition mechanics, index shape, and
  replication lag tuning stay F-DB's; this check cites them.
• A-ARCH-29 (audit-only, conditional on a deployed runtime the project
  operates) checks that availability claims have redundancy behind them: a
  component carrying an availability target runs more than one instance behind a
  health-checked router, or its single instance is recorded with an accepted
  downtime number, and the router removes an unhealthy instance instead of
  continuing to route to it. A stated target above the single-instance baseline
  running one replica with no recorded acceptance is High, as is a replicated
  service with no liveness or readiness probe. A-ARCH-11 remains the home for
  targets with no arithmetic at all; this one is about the means, not the math.
• Two remediation seeds: pin post-write reads to the primary and record the
  staleness budget, and put redundancy behind the availability target.
• Two anti-patterns hunted: replica-served truth (a balance or permission read
  pointed at a replica because it was faster, with no record of the staleness
  that buys) and availability theater (an uptime target with one instance behind
  it, or a replica set whose router has no probe to remove a broken member).
• Surface map gains redundancy and routing signals (replica counts, autoscaling
  ranges, liveness and readiness probes, load-balancer health checks, standby
  and failover declarations, multi-zone placement) and read-routing signals
  (reader endpoints and their call sites, ORM read/write splitting, partition
  and shard key declarations). Conditional sub-surfaces gain a deployed runtime
  the project operates and read replicas, so a library is never graded on
  replicas it never runs.

Changed

• The architecture mirror boundary line records R-ARCH-1..24 defined, up from
  R-ARCH-1..20, matching godplans 1.12.0. The boundary itself stays at 19: the
  audit-only range is numbered by arrival, not renumbered to track godplans,
  because a published check id has to keep resolving to the same check.
• The zero-weight routing note covers A-ARCH-24 through A-ARCH-29 and names
  where each lands: caching and backpressure into integration discipline,
  recovery objectives and read consistency into data architecture and
  invariants, scale-out readiness into component boundaries, redundancy behind
  an availability claim into NFR reality.