Correct module cache hashing docs

[thomhurst]

Closes #3806.

Corrects the module-caching guide to describe actual behavior: input files are content-hashed on every fingerprint calculation, with concurrency bounded by MaximumHashConcurrency.

Validation: git diff --check

[claude]

Code review

Reviewed this doc-only change against the actual implementation.

Verified accurate: The updated wording ("Input files are content-hashed concurrently on every fingerprint calculation, up to MaximumHashConcurrency files at a time") matches ModuleCacheFileHasher.HashAsync (src/ModularPipelines/Caching/ModuleCacheFileHasher.cs), which always SHA-256 hashes file contents via Parallel.ForEachAsync with MaxDegreeOfParallelism = _maximumConcurrency, and is called directly from ModuleCacheResultRepository on each fingerprint calculation. No separate mtime/size-based cache exists to short-circuit hashing, so the old wording ("persistent modification-time and size index; changed files are hashed concurrently") was indeed inaccurate — the fix is correct.

No issues found. This is a minimal, well-scoped documentation correction with no code changes, so there are no architectural or design concerns to raise here.

[thomhurst]

CI diagnosis: the docs deployment and review pass. Ubuntu/Windows/macOS .NET jobs fail only on current-main RunReportTests.cs:1483-1484 CS0117 references to removed flat console options. Focused baseline fix #3864 is running; this PR changes one documentation sentence. No rerun before main is repaired.

[thomhurst]

Shared RunReportTests failure is fixed on current main by merged PR #3844. Refreshed this branch onto current main for a clean CI cycle; no duplicate patch or stale-run rerun.

[thomhurst]

@codex review

[thomhurst]

@claude review

[claude]

Code review

Re-reviewed after the rebase onto current main (no diff content changed since the prior review — still the single-sentence correction in docs/docs/how-to/module-caching.md).

Verified accurate against current main: pulled src/ModularPipelines/Caching/ModuleCacheFileHasher.cs directly from main and confirmed HashAsync always SHA-256 hashes file contents via Parallel.ForEachAsync with MaxDegreeOfParallelism = _maximumConcurrency (bound by MaximumHashConcurrency, matching the option name used in the doc's config sample). There's no persistent mtime/size index that short-circuits hashing — the before/after FileInfo comparison in that method is a race-guard that re-hashes if the file changed mid-read, not a skip-hash cache. So the old wording ("persistent modification-time and size index; changed files are hashed concurrently") was inaccurate, and the new wording ("Input files are content-hashed concurrently on every fingerprint calculation, up to MaximumHashConcurrency files at a time") correctly describes the implementation.

No issues found. This is a minimal, correctly-scoped documentation fix with no code changes — nothing architectural to flag here.

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. 🎉

Reviewed commit: 1b94c42f2c

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[thomhurst]

CI diagnosis: the docs-only diff cannot affect the core test host. The Ubuntu RunCoreUnitTests process exited abruptly with code 134 after ~2 minutes, with no failed-test summary and no hang dump; all other current-head checks and reviews pass. Triggered the single allowed failed-job rerun for this infrastructure/test-host crash.

[thomhurst]

Correction: GitHub reported the workflow rerun was already running, so this agent did not create a duplicate rerun.

[thomhurst]

Refreshed docs-only branch onto current main in c1b8ac0 after the one allowed CI rerun also hit the core-test host failure. Validation: git diff --check clean; PR delta remains only docs/docs/how-to/module-caching.md.

[claude]

Code review

Re-checked after the latest rebase onto main (commit c1b8ac0) — the PR diff is still just the single-sentence correction in docs/docs/how-to/module-caching.md, unchanged from the version already reviewed twice above.

Re-verified against current main: ModuleCacheFileHasher.HashAsync (src/ModularPipelines/Caching/ModuleCacheFileHasher.cs) unconditionally SHA-256-hashes each input file's contents via Parallel.ForEachAsync bounded by MaxDegreeOfParallelism = _maximumConcurrency (sourced from MaximumHashConcurrency), on every call — the before/after FileInfo snapshot is a race guard for files that mutate mid-hash, not a persistent mtime/size cache. The new doc wording ("Input files are content-hashed concurrently on every fingerprint calculation, up to MaximumHashConcurrency files at a time") is accurate; the old wording it replaces was not.

No issues found. Minimal, correctly-scoped documentation fix — nothing architectural to flag.