[codex] Close out SEC proof narrative

[velvetmonkey]

Summary

This closes out the current SEC proof narrative and makes the generated evidence easier to understand without a narrated walkthrough.

Key changes:

• adds a reusable batch Flywheel write path so large SEC report bundles reuse one flywheel-memory subprocess session instead of spawning once per note
• updates company bundle generation to use the batch writer while preserving write-time wikilinks and outgoing-link suggestions
• adds a generated candidate-noise.md report explaining why 31 staged candidates are not active review work
• refreshes the checked-in Markdown-only SEC evidence snapshot with the new candidate-noise page and report links
• updates the README and SEC walkthrough so the public narrative matches the current corpus state

Why

The visible SEC review queue is now clear, but the reports still showed staged candidate counts without explaining why those candidates were not review events. That made the product loop look unfinished or inconsistent.

This PR makes the distinction explicit: the active human review queue is empty, while 31 staged candidates are suppressed because they are duplicate pressure on already-refuted assumptions. That keeps the audit trail visible without asking reviewers to re-adjudicate the same failed assumptions.

The writer change also removes a practical scaling problem: generated report bundles no longer pay subprocess startup cost per Markdown page.

Evidence paths

• evidence/sec-company-ledgers/sec-10y-100-company/reports/company-runs/sec-10y-100-company/index.md
• evidence/sec-company-ledgers/sec-10y-100-company/reports/company-runs/sec-10y-100-company/dashboard.md
• evidence/sec-company-ledgers/sec-10y-100-company/reports/company-runs/sec-10y-100-company/proof-path.md
• evidence/sec-company-ledgers/sec-10y-100-company/reports/company-runs/sec-10y-100-company/review-queue.md
• evidence/sec-company-ledgers/sec-10y-100-company/reports/company-runs/sec-10y-100-company/candidate-noise.md

Validation

• npm run build -w @velvetmonkey/flywheel-ideas-core
• npm run lint -w @velvetmonkey/flywheel-ideas-core
• npm test -w @velvetmonkey/flywheel-ideas-core -- write-subprocess write-dispatcher
• npm test -w @velvetmonkey/flywheel-ideas-core -- company-tracker
• npm test -w @velvetmonkey/flywheel-ideas-core
• real dogfood export through mcp-subprocess: write_path=mcp-subprocess reason=subprocess_ok, exported_markdown=3606

No SQLite, JSON, JSONL, WAL/SHM, or raw SEC cache artifacts are included.