[Sannrox]

Closes #126

A job may declare an input as a sha256: digest of another job's output,
alongside the existing relative paths. The local source resolves that digest
from --inputs-from directories by reading each prior receipt.json. Staging
re-hashes the copy and refuses a mismatch, so a tampered upstream file does
not run. Two receipts chain by digest equality; the receipt schema is
unchanged. Kako still runs one job at a time.

Breaking

kako_core::Input gains a public digest field. Struct literals that omit it
do not compile.

Lane

• claim branch: feat/126
• worktree: .worktrees/issue-126
• base SHA: 503aed94130bffd5bb6add8a033938c3ae5b0a30
• published SHA: 1449907ae27f9cab065cc1e1e02bddeeb4e6df3a
• authority: land

Verification

• cargo fmt --all -- --check
• cargo build --locked --workspace --all-targets
• cargo clippy --locked --workspace --all-targets -- -D warnings
• cargo clippy --locked -p kako-source-sekai --features sekai-client --all-targets -- -D warnings
• cargo test --locked --workspace
• cargo test --locked -p kako-source-sekai --features sekai-client
• bash scripts/validate-workflow-skills.sh
• python3 scripts/adr-index --check

Focused coverage: digest parse, staging mismatch, local digest lookup from a
prior receipt, tampered file refused at staging, parent output names refused,
CLI chain on linux_native (skipped on this host; CI Linux runs it). Isolation
fail-closed tests unchanged. Live isolated-process proof stays the ignored
sekai_live tests.

Autoreview

$AUTOREVIEW --mode local --engine grok --model grok-4.6 --thinking xhigh

Clean: no accepted/actionable findings.

Compatibility

• Receipt JSON is unchanged (receipt_version 6).
• --inputs-from is new on run, validate, preview, and serve.
• The JobSource trait is unchanged; sources resolve digest inputs when they
  yield the job.
• Sekai claim snapshot staging still uses path inputs (digest: None).