Adopt portable KAG index family

[8Dionysus]

Summary

• replace seven tracked KAG monoliths with the portable v3 manifest and 715 bounded content-addressed shards
• pin the blocking repo-local action to aoa-kag b28f64a497fd440dd58cbaae90d655da46224d8c
• update stack topology/source-hygiene validators and the KAG card for the manifest/shard boundary
• preserve exact v2 compatibility through the aoa-kag assembler and dual readers
• record the one-time migration delta with a digest/base-bound receipt

Measured result

• portable family: 21,708,342 tracked bytes
• migration delta: 53,831,710 bytes across 723 generated paths, explicitly receipted
• subsequent generated-delta budget: 1 MiB per PR

Compatibility and validation

• full and incremental portable-family checks
• manifest/shard digest, count, and size validation
• source topology/hygiene regression coverage
• aoa-kag MCP validator: 24 providers, 5 tools, 9 resources
• 21 focused topology and MCP tests

The aoa-4pda rollout canary and its post-merge main gate are green.