feat(config): ingest maintainer focus manifests for repo-specific guidance

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Parent: #32

Goal

Let repo owners tell Gittensory which work areas are wanted, risky, blocked, or preferred.

Requirements

• Support a repo-owned config source such as .gittensory.yml or an API-backed repo settings record.
• Model wanted paths, blocked paths, preferred labels, linked-issue policy, test expectations, maintainer notes, and issue-discovery policy.
• Feed the config into decision packs, local branch preflight, MCP agent planning, and maintainer packets.
• If config is missing or malformed, fall back safely to current deterministic signals.

Acceptance Criteria

• MCP recommendations can say why a repo/path is preferred or discouraged.
• Maintainer-owned config influences miner guidance without becoming public reward optimization.
• Malformed config produces warnings, not crashes.
• No public GitHub output leaks private config fields unless they are explicitly public-safe.

Testing Requirements

This issue must preserve the repo's CI gate:

• npm run test:ci must pass.
• Global coverage must remain at or above 95% for lines, statements, functions, and branches.
• Add or update tests for every new branch, fallback path, sanitizer rule, and regression.
• Add invariant/property-style tests when behavior depends on sorting, gating, public/private boundaries, scoring, queue pressure, or source-upload safety.
• Public GitHub output must be tested against forbidden language: wallet, hotkey, raw trust score, payout, reward estimate, farming, private reviewability, and public score estimate.

Required Test Scenarios

• Valid config.
• Missing config.
• Malformed config.
• Blocked path preflight.
• Preferred path recommendation.
• Public sanitizer regression.