feat(workflows): prefix-cache prompt layout + warm-first fan-out (V3, #2493)

[flora131]

Replacement for #2510 after the stacked-PR base branch was deleted. Same branch, now targeting main (V1 already merged).

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Greptile Summary

This change makes judge prompts reuse a cache-friendly prefix, keeps inline candidate content within UTF-8 byte limits, and prioritizes warm verifier work without changing result order. It also expands coverage for prompt layout, fallback boundaries, concurrency, ordering, and verifier failures.

One P2 repository-style issue remains in the new test: its assertion callback declares an overly broad unknown error parameter instead of the project-required specific error type.

Confidence Score: 4/5

The functional workflow changes are covered by focused tests; merge safety is reduced only by a non-security repository-style violation in the added test.

The final findings contain one non-security P2 issue and no P0 or P1 issues, which maps to a score of 4.

Files Needing Attention: test/unit/verification-prompt-layout.test.ts

Prompt To Fix All With AI

### Issue 1
test/unit/verification-prompt-layout.test.ts:128
**Ambiguous error parameter type**

The new assertion callback explicitly declares `error` as `unknown`, conflicting with the repository convention to use specific types and making the expected failure shape less explicit.

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For each issue above, determine whether it is valid and should be fixed. If so, fix it directly.

_{Reviews (1): Last reviewed commit: "merge origin/main" | Re-trigger Greptile}

Greptile also left 1 inline comment on this PR.

Context used:

• Context used - AGENTS.md (source)

[greptile-apps]

Ambiguous error parameter type

The new assertion callback explicitly declares error as unknown, conflicting with the repository convention to use specific types and making the expected failure shape less explicit.

Context Used: AGENTS.md (source)

Prompt To Fix With AI

This is a comment left during a code review.
Path: test/unit/verification-prompt-layout.test.ts
Line: 128

Comment:
**Ambiguous error parameter type**

The new assertion callback explicitly declares `error` as `unknown`, conflicting with the repository convention to use specific types and making the expected failure shape less explicit.

**Context Used:** AGENTS.md ([source](https://github.com/bastani-inc/atomic/blob/main/AGENTS.md))

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For each issue above, determine whether it is valid and should be fixed. If so, fix it directly.

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