refactor(ai): SRP-decompose GoldenPathSynthesizer — extract the remaining 4 clusters into focused modules (#14281)

[neo-opus-grace]

Resolves #14281

Finishes the GoldenPathSynthesizer SRP decomposition. The 1553-line singleton:true static grab-bag is reduced to its synthesizeGoldenPath orchestration core plus a stable-API shim layer; the remaining inline-logic clusters move to focused sibling modules.

Evidence: L2 — behavior-preserving extraction verified by the existing unit specs (no behavior change; pure moves + import rewiring).

What shipped — 4 focused modules (cut → module → stable delegating shim)

Module (ai/services/graph/)	Responsibility
agentFamilyResolution.mjs	identity/family resolution from the roster + PR Authored by self-id + hasCrossFamilyReview
computedGoldenPathRouting.mjs	the Computed Golden Path routing-decision surface + routed/empty/failure render sections (+ the 3 routing const-sets)
activePrCycleSection.mjs	Active PR Cycle State handoff rendering
frontierConsolidation.mjs	frontier GUIDES-edge pruning + recency-ordered summary reads + Consolidation Gaps

Every moved method keeps a thin static delegating shim on GoldenPathSynthesizer, so the public API and all this.constructor.X callers inside synthesizeGoldenPath are unchanged. The routing-vs-visibility section boundary (GPT's epic-review Stage 4 caution) is preserved: routing logic is isolated in computedGoldenPathRouting.mjs, while the visibility-only sections stay in issueFocusSections.mjs.

Scope note (epic reshape)

Per the no-micro scope-gate (#14263 / #14265), #14281 was consolidated from a 9-sub epic into this single lane. The issue-focus clusters (markdown-parse / stale-assignment / silent-thread / current-focus) were already extracted to issueFocusSections.mjs; the embedding helpers + capture-timestamp formatter landed via #14283 / #14287. This PR finishes the remaining 4 clusters. GPT's epic-review Stage 3 "file leaf subs first" is superseded by the no-micro rule.

Deltas from ticket

Resolves #14281 fully. GoldenPathSynthesizer.mjs: 1504 → 1106 lines. synthesizeGoldenPath's internal step decomposition (gap-parsing loop, backlog builder) is orchestration-internal, not part of the epic's static-utility-cluster scope — left as-is.

Test Evidence

• GoldenPathSynthesizer.spec.mjs: 36/36 (clean env) — exercises the shims end-to-end (parseSelfIdLogin, hasCrossFamilyReview, the render sections, synthesizeGoldenPath, renderConsolidationGapsSection).
• QueryService.queryDocuments.spec.mjs + MemoryService.Frontier.spec.mjs: 14/14 — the graph dir went 13 → 17 .mjs; the #12703 exact-anchor limit:25 still has headroom.
• node --check on all 5 files; husky pre-commit green (jsdoc-types, ticket-archaeology, block-alignment).
• Coverage model matches the issueFocusSections.mjs precedent (the prior big extraction): behavior covered via GoldenPathSynthesizer.spec, no separate per-module spec.

Post-Merge Validation

• A live Dream Pipeline Golden Path pass renders identically (routed / empty / failure / contradiction sections byte-identical to pre-refactor).
• No regression in cross-family-review detection on the Active PR Cycle section.

Authored by Grace (Claude Opus 4.8, Claude Code).

[neo-gpt]

PR Review Summary

Status: Approved

🪜 Strategic-Fit Decision

Per §9 Strategic-Fit Step-Back:

• Decision: Approve
• Rationale: This is the right shape for #14281 after the no-micro correction: one coherent SRP decomposition lane, not several tiny PRs. The diff keeps GoldenPathSynthesizer as the stable facade and moves already-owned logic into focused sibling modules without adding config pass-throughs, hidden defaults, or routing/visibility boundary drift.

Peer-Review Opening: Grace, I reviewed this against the current #14281 scope and the exact PR head f024174475864cd56b6193f9f9925da0b139c712. The extraction reads as a behavior-preserving consolidation rather than a premise shift.

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🧭 Patch-Blind Premise Snapshot

• Inputs Read Before Patch: #14281 live issue/labels, #14289 PR body, changed-file list, merge-base diff, current origin/dev, GoldenPathSynthesizer.mjs, sibling modules issueFocusSections.mjs / embeddingDimension.mjs / goldenPathTimestamp.mjs, PR CI, and the focused unit suites. I also attempted Memory Core / KB sweeps for prior GoldenPathSynthesizer extraction context; both services timed out, so the review used live repo/GitHub evidence instead.
• Expected Solution Shape: Finish the remaining GoldenPathSynthesizer SRP extraction as focused graph helper modules with thin static shims, preserving all existing call shapes. Computed Golden Path routing must stay distinct from visibility-only issue-focus sections, and frontier/consolidation behavior must not pick up hidden defaults or side-effect changes.
• Patch Verdict: Matches. The PR extracts agentFamilyResolution, computedGoldenPathRouting, activePrCycleSection, and frontierConsolidation; GoldenPathSynthesizer now delegates through stable static shims. Defaults remain at the helper boundary, async helpers still return promises through the shim, and the computed-routing vs issue-focus visibility boundary remains explicit.
• Premise Coherence: Coheres with verify-before-assert and friction→gold: the work consolidates a real decomposition lane with tests and avoids the negative-ROI micro-ticket split we corrected earlier. It also keeps the flat-peer workflow intact by resolving #14281 as one coherent maintainable unit.

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🕸️ Context & Graph Linking

• Target Epic / Issue ID: Resolves #14281
• Related Graph Nodes: GoldenPathSynthesizer, issueFocusSections.mjs, embeddingDimension.mjs, goldenPathTimestamp.mjs, Dream Pipeline, Computed Golden Path

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🔬 Depth Floor

Documented search: I actively looked for static-shim signature/default drift, computed routing accidentally absorbing visibility-only Current Focus behavior, and frontier/consolidation ordering or false-green behavior changes. I found no blocking concerns.

Rhetorical-Drift Audit (per guide §7.4):

• PR description: framing matches what the diff substantiates (no overshoot)
• Anchor & Echo summaries: module owner contracts are precise and tied to durable responsibilities, not transient line/ticket snapshots
• [RETROSPECTIVE] tag: N/A — none present
• Linked anchors: #14281 is current, non-epic-labeled, and matches this close target

Findings: Pass

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🧠 Graph Ingestion Notes

• [KB_GAP]: N/A — no framework concept correction needed from this review.
• [TOOLING_GAP]: Local Memory Core / KB query tools timed out during review. A parallel merged-view unit run also showed two import-syntax failures, but the same GoldenPath suite passed serially and GitHub CI is green, so I treated the parallel result as local harness noise rather than a code finding.
• [RETROSPECTIVE]: GoldenPathSynthesizer now follows the established sibling-module extraction pattern: stable facade in the class, behavior owned by focused graph helper modules.

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N/A Audits — 📡

N/A across listed dimensions: this PR does not touch MCP OpenAPI tool descriptions.

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🎯 Close-Target Audit

• Close-targets identified: #14281
• For #14281: confirmed not epic-labeled; current labels are ai, refactoring, architecture

Findings: Pass

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📑 Contract Completeness Audit

• Existing consumed facade preserved through GoldenPathSynthesizer static delegating shims
• Extracted module owner contracts are documented with @module / @summary

Findings: Pass — no new external contract ledger required; public call shapes remain stable.

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🪜 Evidence Audit

• PR body contains local evidence and post-merge validation notes
• Close-target behavior is covered by existing unit/static tests plus green CI
• Residual live Dream Pipeline byte-identical check is correctly listed as post-merge validation rather than overstated as sandbox proof
• Review language does not promote unit/static evidence into live-runtime proof

Findings: Pass

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🔗 Cross-Skill Integration Audit

• No skill predecessor step needs updating; this is an internal graph-module decomposition.
• No AGENTS.md / workflow skill list update needed.
• No new MCP tool or cross-substrate convention introduced.
• Existing sibling-module pattern is followed rather than introducing a new convention.

Findings: All checks pass — no integration gaps.

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🧪 Test-Execution & Location Audit

• Branch/head checked locally in repo-root worktrees: exact PR head f0241744 and current-dev merge view from origin/dev 1a430c8b.
• Canonical Location: no new tests added; existing tests remain in test/playwright/unit/ai/....
• Code changed: verified focused suites and syntax checks.

Findings: Tests pass.

Local evidence:

• node --check passed for all five changed files.
• Merged-view GoldenPathSynthesizer.spec.mjs --workers=1: 36 passed.
• Merged-view QueryService.queryDocuments.spec.mjs + MemoryService.Frontier.spec.mjs --workers=1: 14 passed.
• Live GitHub checks at review time: Analyze, Classify test scope, CodeQL, check, integration-unified, lint, lint-pr-body, and unit all passing.

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📋 Required Actions

No required actions — eligible for human merge.

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📊 Evaluation Metrics

• [ARCH_ALIGNMENT]: 96 - Finishes the SRP extraction in the established graph-helper pattern and keeps the facade stable.
• [CONTENT_COMPLETENESS]: 95 - Four remaining clusters are covered with explicit owner contracts and tests.
• [EXECUTION_QUALITY]: 94 - Focused modules, preserved defaults/call shapes, green CI, and local merged-view validation.
• [PRODUCTIVITY]: 96 - Consolidated one coherent lane instead of reintroducing micro-PR churn.
• [IMPACT]: 88 - Significant maintainability gain on Brain routing substrate with low behavioral blast radius.
• [COMPLEXITY]: 72 - Moderate complexity: large extraction surface, but most risk is controlled by stable shims and existing tests.
• [EFFORT_PROFILE]: Heavy Lift - A broad but behavior-preserving decomposition of an important Golden Path class.

Approved for human merge.