chore: add Copilot PR review instructions

[SgtPooki]

Summary

Adds .github/copilot-instructions.md to guide GitHub Copilot's PR review toward high-signal, dealbot-specific feedback and away from CI-duplicate noise.

Process

• Platform research: reviewed Copilot's review constraints (4000-char base-branch read, Comment-only review, no merge gating, no external link following) plus Google/Microsoft/OWASP/NIST review literature.
• Empirical analysis: analyzed 319 Copilot inline comments across the last 150 dealbot PRs. Identified where Copilot reviews well (job-state consistency, test/fixture-contract drift, multi-network behavior, quoted SQL identifiers, redaction — PRs feat: add sp blocklist to skip checks for specific providers #452, feat: add network column to schema for multi-network support #463, fix: landing page doesn't show blocked SPs #471, feat(web): add network switcher #472, fix: redact RPC tokens from logged deal errors #453) versus where it overreaches (generic-SQL assumptions on ClickHouse code — PRs feat: write event data to clickhouse  #438, feat: add retrieval_type column to retrieval_checks clickhouse table #485; low-priority frontend optimization comments).
• Adversarial iteration: ran self-review against the evidence, then a second-opinion review (Codex) to tighten wording, fit the 4000-byte budget, and encode dealbot-specific invariants. Three diff rounds.

What's encoded

• Context: monorepo layout, Postgres = source of truth, ClickHouse cluster/schema/migrations owned by external team — review CH-touching code for dealbot impact (payload shape, producer correctness, ops regressions); skip CH schema/retention/ops design suggestions.
• Core invariants:
  • at most one job per SP per check type per network at a time
  • jobs fail only on execution failure, not on negative check results
  • scheduling, cleanup, active-provider filtering, and queue execution agree on the same SP set and network
  • network-aware code carries the same network invariants across inserts, queries, conflict keys, filters, and tests
• Blocker / Important priorities aligned to observed high-value themes.
• Do Not Comment On list to suppress noise already covered by CI (Biome, build, typecheck, test, Docker, conventional-commit PR titles).

Final size: 3890 / 4000 bytes (~110 byte headroom).

Notes for reviewers

• Copilot reads custom instructions from the base branch, so this PR will not exercise its own instructions. Land first; evaluate on subsequent PRs.
• Comments that drove specific lines:
  • CH ownership wording: PRs feat: write event data to clickhouse  #438, feat: add retrieval_type column to retrieval_checks clickhouse table #485
  • Network invariants and "per network" precision: PR feat: add network column to schema for multi-network support #463
  • Provider blocklist drift (selection vs execution): PR feat: add sp blocklist to skip checks for specific providers #452
  • Quoted Postgres identifier / NULL NOT IN semantics: PR fix: landing page doesn't show blocked SPs #471
  • Frontend UX vs low-impact optimization framing: PR feat(web): add network switcher #472
  • Token redaction / logging: PR fix: redact RPC tokens from logged deal errors #453

Test plan

• Confirm file is under 4000 bytes (wc -c .github/copilot-instructions.md)
• After merge, observe Copilot review behavior on the next 5–10 PRs
• Track whether CI-duplicate noise drops and whether ClickHouse generic-SQL false positives stop appearing
• Iterate (add path-specific .github/instructions/*.instructions.md overlays only if repeated patterns emerge)

[Copilot]

Pull request overview

Adds a repository-level .github/copilot-instructions.md file to steer GitHub Copilot’s PR review behavior toward dealbot-specific, high-signal correctness/invariant feedback and away from CI-duplicate noise.

Changes:

• Introduce a structured PR review rubric (goal, philosophy, priorities, invariants, “do not comment” list).
• Encode dealbot-specific guidance around job/check invariants, multi-network correctness, and provider filtering/blocklists.
• Define a suggested one-issue-per-comment output format for reviews.

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💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[rvagg]

nice, will be interesting to see if this makes a noticeable difference