feat(review): consolidate output into a single file

[ryzizub]

Description

The /review skill (and the review step in /build) currently writes findings across four separate files in docs/code-review/ (or docs/reviews/ during /build), one per quality-review agent. Jumping between four files to understand one review makes triage slower than reading the diff itself — the navigation overhead often outweighs the value of the findings.

Proposal: emit a single consolidated review.md as the primary artifact, with per-agent findings grouped into sections within that file. Raw per-agent outputs may optionally live in a review-raw/ subdirectory for debugging, but the user-facing artifact is one file.

Requirements

• /review produces a single consolidated markdown file as its primary output.
• The review step inside /build produces the same single-file output.
• Existing quality-review agents (vgv-review-agent, code-simplicity-review-agent, test-quality-review-agent, architecture-review-agent) still contribute findings, grouped by agent within the consolidated file.
• Chat summary points to sections within the single file, not to separate files.
• Cleanup logic for ephemeral review output (under docs/reviews/ and docs/hotfix-review/) continues to work with the new layout.

Additional Context

• Companion to the alignment issue (fix(review): align chat summary with review content #179) — IDs and summary/file alignment apply whether findings live in one file or several, and both issues land cleaner together.
• Out of scope: severity tiers, interactive triage, GitHub comment bridge, self-review vs PR-review scope split (tracked separately).

[Statyk7]

Also I suggest we name the file after the current branch or the changes in case the use wants to keep it.