[ccch1mneyyy]

Closes #330

What was wrong

ops_replace bounded match counts but not the resulting file size. A 40 KB source containing 40,000 a characters and a 1 KiB replacement produced 40,960,000 bytes, beyond the 32 MiB file-write ceiling. Checking only during publication would also leave earlier directory targets changed before a later oversized target failed.

The change

• Export and reuse the existing ops-files 32 MiB file-content constant, rather than duplicate the limit.
• Compute each planned output's UTF-8 byte size with checked multiply/subtract/add operations before constructing replacement content or publishing any file. Overflow and over-limit plans return OUTPUT_LIMIT with no file changes.
• Apply the same planning bound to previews; exactly 32 MiB remains supported. Keep maxReplacements, existing revision/locking behavior and mutation authority unchanged.
• Add arithmetic unit coverage and real-worker boundary, multibyte and multi-file regressions. Update paired component docs and changelog; no new dependency or tool-schema change.

Validation

cargo test --workspace --locked --manifest-path native/Cargo.toml
  43 Rust unit tests passed, 0 failed, 0 ignored
  includes replacement boundary, shrink and arithmetic overflow cases

npm run build && npm run build:ptc
  rebuilt/staged the modified worker; passed

DSH_OPS_REQUIRE_RUNTIME=1 node test/run.mjs replace-size linux-args replace-concurrency
  3 suites passed, 0 skipped, 0 failed
  replace-size: all 3 checks passed
  exact 32 MiB accepted; +1 byte rejected
  UTF-8 bytes (not character count) enforced
  later oversized directory target leaves earlier files unchanged
  preview and execution both covered

node scripts/verify-gate.mjs --skip-install
  linux-x64: gate green
  125 suites passed; 2 skipped (optional external tui-host/tui-native)
  manifest: 73 checks (minimum 59)
  packed release and runtime closure: passed

Red/green using the unmodified main worker:
  replace-size: 3 of 3 checks fail
  fixed, rebuilt worker: all 3 checks pass

The full gate uses the real Landlock backend to separate main's unrelated bwrap cache defect (#337/#338); no sandbox permission relaxation is introduced. Input/output schema and model-description byte delta: 0.

PR-triggered CI: https://github.com/T-Auto/dsh-ops/actions/runs/39480498372 — pull_request, aggregate CI required: SUCCESS (Windows x64, Linux x64, macOS arm64 and required supporting jobs passed).

Environment

Arch Linux x64, Node 24.21.0, Rust 1.97.1; source checkout based on main a9ff940.

Combined local validation

The submitted heads of #338, #340, #341, #342, #343, #344 and #345 were applied together in an isolated local verification worktree, including their combined changelog entries. With ordinary PATH selecting real bwrap 0.13.0 and real dsh-TUI 0.16.1 host/worker/renderer suites enabled, node scripts/verify-gate.mjs --skip-install passed all 11 release-gate steps: 129 suites passed, 0 skipped; 46 Rust unit tests passed; manifest 73/59. This Linux combined-tree evidence is separate from each PR's own cross-platform CI; no upstream merge or host installation was performed.