fix(audit): close the OX low table against its own list (OX-L1..L19)

[ojassug]

Audit OX-L1 through OX-L19. DECISIONS §69. Six fixed, five recorded at their sites, three
already "no action" in the audit itself — every row dispositioned.

max_audit.md's LOW table went unscheduled and was found open weeks later (§55). The lesson
recorded then was close a document against its own list of findings, not against the list of work
that was done. So the "not fixed" half is written down too — that is the half that goes missing.

Fixed

id	what
L6	The per-session seen-hash cap was a bare 1000 inside capSeenBlockHashes while sessionTtlMs, maxSessions and maxContentEntriesPerSession were all settable — the one bound that grows with conversation length was the one nobody could tune. Now GatewayConfig.maxSeenBlockHashesPerSession, same default.
L7	The MCP overflow check ran before processBuffer and then cleared the whole buffer, so a chunk carrying complete requests followed by one oversized partial discarded the complete ones too. They were well-formed, already received, answerable. Draining first leaves exactly the un-terminated remainder for the limit to judge.
L9	The bench loader's limits merge could never fire — ResolvedConfig has no such field, which is why it needed two as unknown as Record<string, unknown> casts. Deleting it also removed an as unknown as ResolvedConfig that was disabling type checking for every other key in that literal.
L10	Dataset routing matched includes('humaneval') before checking for a real path, so ./fixtures/humaneval-comparison-2026.jsonl was silently answered with the bundled dataset. Now exact name → path → substring as last resort.
L12	package.json and src/version.ts are hand-synced; a test now pins them equal. Not restructured — version.ts stays the single source per the release procedure — so this closes the drift class rather than the duplication.
L19	.gitignore was the full GitHub Python template: 245 lines, ~111 entries, Django through pdm, none of it used, with the dozen working entries buried at the bottom. Now 44 lines / 25 entries, keeping a real Python block for tokendamper-benchmark/.

L6, L7, L10 and L12 are pinned by test/unit/audit-ox-low-findings.test.ts. L6 and L7 were
mutation-checked — reverting either source file fails its test and only its test. L19 was verified
by diffing git status --porcelain across the change: nothing became newly visible.

Recorded at their sites, not fixed

• L1 — expectedSavings: 0.45 is unconsumed, and the number isn't a measurement either (the
  same corpus reduces ~20% on TypeScript, ~16% on Python). Left per the frozen-model precedent H4
  set and OX-H5 followed: nobody can set it, so it misleads no caller. Wiring it means deriving a
  real estimate from the selected stages — a planner change.
• L8 — the MCP shutdown flush race. The fix is to stop forcing the exit and let the loop drain,
  but stop() only removes the data listener; whether the process then exits depends on stream
  state that file doesn't control, and getting it wrong hangs tokendamper mcp on Ctrl+C.
  Delivering SIGINT to exercise that isn't something this suite can do. Same call as L4.
• L13 — /health exposing sessionCount is M8/M9's question. On loopback it isn't a leak;
  on an exposed bind it is, and that's exactly the configuration those two decide. Answering it
  twice in two places is how two answers drift.
• L17, L18 — architecture import linting and coverage tooling both need a new devDependency.
  The audit calls both optional; adding dependencies to someone's package on the strength of a LOW
  finding isn't a call to make unasked. Both are one command away when wanted.
• L14, L15, L16 were "no action" in the audit itself and remain so.

What this does not establish

• Nothing about M8, M9 or M15 — all three are decisions rather than work, and all three are
  still open. L13 is now explicitly folded into M9.
• L19's prune is verified only against the current tree. git status showing nothing newly
  visible proves no existing file lost its ignore. A file type that doesn't happen to exist right
  now, covered by a removed template line, wouldn't have been caught.

Verification

npm run typecheck, npm run lint, npm run build and npx vitest run all pass: 91 files /
826 tests.

🤖 Generated with Claude Code