fix(scripts): selfhost-env-reference generator misses same-file wrapper helpers like envDurationMs

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⚠️ Definition of Done: this issue must be completed in full, in a single PR. Do not split this
work across multiple PRs, and do not defer any Deliverable below to a follow-up issue. A PR that
satisfies only some of the Deliverables, stubs a required test, or leaves a checkbox
partially-done does NOT resolve this issue and will be closed.

Context

scripts/gen-selfhost-env-reference.ts (lines 119-132) recognizes an env.SOMETHING-style read
via three mechanisms: a literal string, the envString(env, "X") helper, or a call to a helper
registered in PROCESS_ENV_NAME_HELPERS/ENV_NAME_LITERAL_ARG_HELPERS where the env-var name is
passed as a literal argument. It has no case for a same-file wrapper function that forwards its own
name parameter (not a literal) into one of the recognized helpers.

Two real instances of this blind spot exist today:

• src/selfhost/queue-common.ts:1096-1098 defines envDurationMs(name, fallback), which calls
  parsePositiveIntEnv(name, {...}) with name as a parameter. It's called with 5 real literal env
  var names: QUEUE_STARTUP_JITTER_MS (line 712), QUEUE_RECOVERY_JITTER_MS (716),
  QUEUE_PROCESSING_TIMEOUT_MS (720), QUEUE_DEAD_LETTER_REVIVE_INTERVAL_MS (742), and
  SCHEDULED_ENQUEUE_JITTER_MS (763).
• src/selfhost/maintenance-admission.ts:152-157 defines its own local
  parsePositiveFloatEnv(name, fallback) wrapper, called at lines 185-188 with
  MAINTENANCE_ADMISSION_MAX_HOST_LOAD.

None of these 6 env vars appear in the generated apps/loopover-ui/src/lib/selfhost-env-reference.ts
(confirmed by grep), nor in .env.example (QUEUE_DEAD_LETTER_REVIVE_INTERVAL_MS is mentioned only
in prose docs, never as a settable var listing). These are real, operator-tunable knobs, documented
in their own code comments, that silently never reach the self-host operator reference table — and
because the generator's own helper-detection logic has this blind spot, npm run selfhost:env-reference -- --check can never flag them as stale, no matter how carefully a
contributor regenerates the file. This is the same class of bug already fixed twice for other blind
spots (#6994, #8627, and the globalThis-cast/severity-threshold fix in #8632) — this is the third,
distinct instance (same-file wrapper functions), not a duplicate of either.

Requirements

• Extend gen-selfhost-env-reference.ts's helper-detection logic to recognize a same-file wrapper
  function whose single string parameter is forwarded, unmodified, into an already-recognized
  helper (parsePositiveIntEnv, parsePositiveFloatEnv, or the existing literal-arg helpers) —
  either by adding envDurationMs and the local parsePositiveFloatEnv pattern to the existing
  helper-detection maps, or by generalizing detection to any single-string-param function that
  forwards its first argument this way.
• The fix must generalize enough to also catch maintenance-admission.ts's locally-defined
  parsePositiveFloatEnv, not just special-case envDurationMs by name.

Deliverables

• collectSelfHostEnvVars() (or the equivalent scan entry point) includes
  QUEUE_STARTUP_JITTER_MS, QUEUE_RECOVERY_JITTER_MS, QUEUE_PROCESSING_TIMEOUT_MS,
  QUEUE_DEAD_LETTER_REVIVE_INTERVAL_MS, and SCHEDULED_ENQUEUE_JITTER_MS (currently absent).
• collectSelfHostEnvVars() includes MAINTENANCE_ADMISSION_MAX_HOST_LOAD (currently absent).
• The generated apps/loopover-ui/src/lib/selfhost-env-reference.ts is regenerated (npm run selfhost:env-reference) and committed with all 6 new entries present.
• A new test in test/unit/selfhost-env-reference-script.test.ts, using the existing fixture
  pattern, proving a same-file wrapper function forwarding its name parameter into
  parsePositiveIntEnv/parsePositiveFloatEnv is now detected.

All four Deliverables are required in the same PR.

Test Coverage Requirements

scripts/** generator logic and its test file are both measured by codecov/patch (99%+ target).
The new test must exercise the new wrapper-detection code path directly (a fixture module defining
a wrapper function shaped like envDurationMs), not just re-assert already-covered helper patterns.

Expected Outcome

All 6 real, currently-invisible self-host env vars appear in the generated operator-facing
reference table, and the generator's helper-detection logic now generalizes to same-file
parameter-forwarding wrappers, closing this blind-spot category rather than just these 6 instances.

Links & Resources

• scripts/gen-selfhost-env-reference.ts:119-132 (helper-detection maps to extend)
• src/selfhost/queue-common.ts:1096-1098 (envDurationMs), lines 712, 716, 720, 742, 763 (call
  sites)
• src/selfhost/maintenance-admission.ts:152-157 (local parsePositiveFloatEnv), lines 185-188
  (call site)
• test/unit/selfhost-env-reference-script.test.ts (existing fixture pattern to extend)
• Prior fixes to the same generator: miner env-reference generator misses coding-agent driver env vars #6994, selfhost-env-reference generator misses POSTHOG_SERVER_NAME/POSTHOG_MIN_SEVERITY/POSTHOG_REPO_MIN_SEVERITY #8627, fix(scripts): detect globalThis-cast and severity-threshold env reads #8632 (each a distinct blind spot in the same
  script — see also the sibling issue for the for (const name of ARRAY) blind spot found in the
  same audit)

[linear-code]

JSO-6001