chore(startup): remove server-init.ts, a module nothing imports

[maxmad64bis]

⚠️ base-red inherited: #9985

Summary

• src/server-init.ts is never imported. The Next.js instrumentation hook
  (src/instrumentation-node.ts) is the boot path that runs, and it already performs every
  initialization this module declares — checked call by call.
• The module is not merely inert, it misleads: wiring added to it never executes. That is what
  happened in fix(server): wire credential health scheduler into serve boot #7432 (credential health) and [BUG] Claude adaptive-thinking corrupts tool calls & leaks </think> on Cursor/OpenAI path; Thinking Budget UI is a no-op #5312 (thinking budget), and both left regression tests
  asserting the wiring must not live there.
• Removes it, corrects the four comments naming it as the caller (arenaEloSync.ts,
  openrouterProviderStats.ts, modelsDevSync.ts, pricingSync.ts — the real caller is
  instrumentation-node.ts in all four), and the doc and .env.example references that pointed at
  the file.

Related Issues

• Related to fix(server): wire credential health scheduler into serve boot #7432 and [BUG] Claude adaptive-thinking corrupts tool calls & leaks </think> on Cursor/OpenAI path; Thinking Budget UI is a no-op #5312 — both were caused by wiring landing in this module.

Validation

• Change type: other (dead-code removal)
• Focused tests and category gates from the golden path: the four suites that asserted on the
  module (82 pass, 2 skipped), npm run test:vitest (368/368), npm run check:docs-all
• npm run lint
• Reconciled with the current active release base; focused checks rerun afterward
• Production-code changes include a new or updated automated test in this PR
• SonarQube is temporarily opt-in while the private project has no quota; it is not a PR gate.

Tests Added Or Updated

• tests/integration/integration-wiring.test.ts
• tests/integration/security-hardening.test.ts
• tests/unit/lib/jobRegistry/boot-wiring.test.ts
• tests/unit/cleanup-column-fix.test.mjs
• tests/unit/thinking-budget-hydration-5312.test.ts (comment only)

Assertions that only read the server-init.ts source are removed, or redirected to the live path
(instrumentation-node.ts, initCloudSync.ts), so they now cover the module that actually runs.

Coverage Notes

• No production code is added: a file is deleted together with the assertions that only described
  it. The live boot path keeps its coverage and is now asserted directly instead of through the
  dead module.

Reviewer Notes

• No behavior change — the module never executed.
• Localized copies under docs/i18n/ still name the file. They are generated and catch up on the
  next translation run.
• Overlaps with chore(security): drop the unused enforceSecrets() duplicate #10775 on src/server-init.ts and two test files. Both are independently
  mergeable; whichever lands second needs a trivial rebase.
• npm run check:docs-all still reports two failures (BOT_TOKEN / BOT_URL absent from
  .env.example, executors count in ARCHITECTURE.md). Both are pre-existing and outside this
  diff — the diff touches one line in each of .env.example and ENVIRONMENT.md.

[maxmad64bis]

Rebased onto bc6129bcb — the conflict is gone (MERGEABLE).

The conflict came from #10775, which landed first and touched the same module: it removed enforceSecrets() from src/server-init.ts and dropped the matching assertions. Resolution kept this PR's intent, which is a superset — the whole module goes:

• src/server-init.ts — deleted (modify/delete).
• tests/integration/integration-wiring.test.ts — the Pipeline Wiring — server-init.ts block is removed entirely rather than trimmed.
• tests/integration/security-hardening.test.ts — dropped from the diff: chore(security): drop the unused enforceSecrets() duplicate #10775 already applied those 6 lines. The PR is now 17 files instead of 18.

Re-ran after the rebase: the 7 affected test files pass (105 tests, 0 failing, 4 skipped), npm run test:vitest 368/368, npm run lint 0 violations.

All 7 red checks on this run are inherited base-red, none of them from this diff:

Check	Cause
Docs Gates (fast-path)	5 strict drifts, all the provider count 342 vs the live 343 (PROVIDER_REFERENCE.md + 4 SVGs) — files this PR does not touch. Named in the #9985 verdict for the 3810a6c52..bc6129bcb range.
Fast Quality Gates	same failure on unrelated PRs cut from the same base.
Unit Tests fast-path 1/4 … 4/4	same four shards fail on unrelated PRs cut from the same base.
No new ESLint warnings	the ratchet fails on i18nUiCoverage.pct: 99.4 < baseline 100. This diff contains no UI file and no locale file, so it cannot move that metric.

⚠️ base-red inherited: #9985