docs: define shared development workflow

[benstein]

What changed

• Added repository-wide branch, commit, Linear, PR, and merge guidance to the root AGENTS.md.
• Required Conventional Commits and Linear issue footers when applicable.
• Defined Linear branch naming and non-ticket fallback naming.
• Required Linear updates through MCP from active work through merge.
• Clarified that shared workflow guidance belongs only in the root file; nested AGENTS.md files remain application-specific.
• Added safeguards against mixing unrelated work, inventing ticket references, marking tickets Done before merge, and merging without explicit authorization.

Areas affected

• Server
• Dashboard
• Collection
• Website
• Shared documentation, CI, or deployment

Contracts and data

• No API, report-schema, authentication, deep-link, season-metric, or database contract changed
• Every affected producer and consumer was updated together
• Tenant and source-team visibility was reviewed
• No credentials, production data, or private scouting notes are included

Verification

• ./scripts/check-structure.sh: passed.
• git diff --check: passed.
• Confirmed the commit changes only the root AGENTS.md.
• Focused independent review found no Critical, Important, or Minor issues.

Deployment

Documentation-only change. No runtime, provider, migration, environment-variable, or release behavior changes.

[railway-app]

This PR was not deployed automatically as @benstein does not have access to the Railway project.

In order to get automatic PR deploys, please add @benstein to your workspace on Railway.

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-08-31T19:16:00.678489Z	b5f453e	PR opened
🔒 Security Review	✅ Completed 2026-08-31T19:18:09.079098Z	b5f453e	PR opened

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