Issue 29: deterministic examples hygiene

[DerekCorniello]

Local Derek-authored remediation stack for issue 29. Makes the runner safe under failures and concurrent use, validates selectors, removes compiled outputs, and adds CI assertions.

[greptile-apps]

Greptile Summary

The PR hardens deterministic example validation and repository hygiene.

• Uses collision-safe temporary diff files with signal-aware cleanup.
• Rejects invalid selectors and removes generated example artifacts after execution.
• Adds CI detection for compiled executables left under examples/.
• Consolidates contributor guidance in AGENTS.md and intentionally removes the redundant Claude bridge.

Confidence Score: 5/5

The PR appears safe to merge.

No blocking failure remains.

Important Files Changed

Filename	Overview
scripts/run-examples.sh	Adds selector validation, safer temporary-file handling, and cleanup of generated example artifacts.
.github/workflows/examples.yml	Adds a post-run assertion that rejects compiled example executables left in the checkout.
AGENTS.md	Reorganizes contributor guidance around deterministic examples, repository invariants, and the quality gate.
CLAUDE.md	Removes the AGENTS.md bridge in accordance with the stated repository organization policy.

_{Reviews (2): Last reviewed commit: "fix(examples): clean temporary runner fi..." | Re-trigger Greptile}

[DerekCorniello]

@greptile-apps please re-review against the current head. Removing CLAUDE.md is intentional organization policy: every repository retains AGENTS.md, and CLAUDE.md only contained the bridge to it.