[MaojiaSheng]

Description

以保存 GitHub Personal Access Token（PAT）为例：

# 首次写入或轮换 GitHub PAT；credential/github 是 target，pat 是 field
ov privacy upsert credential github --field-pat 'github_pat_...'

# target 只有 pat 一个字段时可以省略 field
ov privacy reference credential github
ov privacy resolve credential github

# 显式指定 field 的等价形式
ov privacy reference credential github pat
ov privacy resolve credential github pat
ov privacy resolve '{{ov_privacy:alice:viking://~/privacy/credential/github#/values/pat}}'

# 查看/切换历史版本，或删除 pat 字段（最后一个字段删除后 target 也会删除）
ov privacy versions credential github
ov privacy activate credential github 1
ov privacy delete credential github pat --yes

# 扫描一个明确的 URI；默认仅报告，--fix 才会替换明文 PAT
ov privacy scan --uri viking://~/resources/project-a

Human Involvement

• A human participated in the implementation or review loop
• This PR was generated entirely by AI agents without human participation in the loop

Related Issue

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Refactoring (no functional changes)
• Performance improvement
• Test update

Changes Made

• Extended ov privacy with field-oriented upsert, reference, resolve, delete, version, and URI-scoped scan workflows.
• Added owner-bound Privacy references with safe single-field discovery and explicit plaintext resolution.
• Added server-side atomic field PATCH, field deletion, target cleanup, identifier validation, and payload capacity limits.
• Added a native Rust Aho-Corasick Privacy matcher with PyO3 bindings, bounded match allocation, and process-local revision/TTL caching.
• Applied deterministic Privacy sanitization before persistence and indexing across content writes, Skills, Resources, and direct VikingFS text writes.
• Added fail-closed handling for ambiguous values, oversized content, and excessively dense replacements.
• Added bounded ov privacy scan --uri dry-run/repair support with node, file-size, byte, match, repair, duration, rate, and concurrency limits.
• Unified one shared PrivacySanitizer instance across service components and bounded visible-read sanitization.
• Updated bilingual Privacy API/concept documentation and GitHub PAT examples.
• Added API, service, sanitizer, write-path, validation, scan, concurrency, dotfile, and Skill-description regression coverage.

Testing

• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I have tested this on the following platforms:
  • Linux
  • macOS
  • Windows

Checklist

• My code follows the project's coding style
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• Any dependent changes have been merged and published

Screenshots (if applicable)

Additional Notes

[yeshion23333]

已复现两个需要修复的正确性问题：更新 Skill 会删除其正文仍在引用的 Privacy 配置；追加写入时，若已登记的密钥跨越追加边界，完整密钥会绕过脱敏，以明文落盘并进入后续索引。