Add weekly research heartbeat

[Sparvovic]

What changed

• add a repo-specific AGENTS.md with verified commands and research rules
• add a reusable weekly research workflow with missed-run catch-up behavior
• add the first dated research report covering official Codex sources, GitHub projects, and qualified X signals
• tighten subagent cost guidance with a one-agent default, a two-to-four-worker starting range, and documented shallow-depth defaults
• expose the workflow through the README, prompt library, source map, and package validator
• ignore local .tools/ binaries during public-content validation

Why

The scheduled 09:00 heartbeat did not run, so this catch-up run turns the maintenance process into a durable, reviewable repository workflow. Future runs can distinguish official facts from community discovery and record explicit adopt, watch, test isolated, or ignore decisions.

User impact

Maintainers get a repeatable way to keep Flightdeck current without reacting to every new repository or social post. Users get clearer cost controls for subagents and a public decision trail for adopted guidance.

Validation

• python scripts/validate.py — passed, 42 text files checked
• git diff --check — passed
• manual review of the full diff and public-source links
• public-risk scan is part of scripts/validate.py

Remaining risk

Community signals are intentionally treated as discovery, not product evidence. The optional agnix linter and one-agent versus multi-agent benchmark remain deferred until they can be tested in isolation.