api-reference: document the 8 AI SRE knowledge endpoints

[ysyneu]

What

Adds OpenAPI documentation for the eight app_key-callable AI SRE knowledge APIs, under a new AI SRE/Knowledge tag (zh: AI SRE/知识):

Method	Endpoint	Operation
POST	/safari/knowledge/pack/list	List knowledge packs
POST	/safari/knowledge/get	Get account knowledge pack
POST	/safari/knowledge/pack/ensure	Ensure knowledge pack (idempotent create)
POST	/safari/knowledge/pack/update	Update knowledge pack (scope move)
POST	/safari/knowledge/pack/delete	Delete knowledge pack
POST	/safari/knowledge/file/list	List knowledge files
POST	/safari/knowledge/file/get	Get knowledge file (returns content_b64)
POST	/safari/knowledge/file/put	Upload knowledge file (base64 in JSON, not multipart)

The legacy /safari/knowledge/save-from-session route is not app_key-callable and is intentionally not documented.

Details

• Request/response schemas are lifted from the backend handlers (KnowledgePackItem, KnowledgeFileItem, KnowledgeWarning + per-operation request/response schemas); epoch-millisecond fields are described as Unix timestamps in milliseconds so SDK generators map them correctly.
• Each operation carries a Restrictions table (per-account rate limits from the gateway registry: reads 50/s + 1,000/min, writes 20/s + 300/min; write operations gated by the Knowledge Manage permission and audit-logged) plus Usage bullets for non-obvious behavior (lazy account-pack creation, scope-move conflict semantics, UTF-8-only content, base64 upload).
• Response examples are real 200s captured from the dev API (list/get examples trimmed to 1–2 items; the temp file used for the file examples was deleted afterwards).
• The 8 operations are merged into safari.openapi.{en,zh}.json (33 → 41 paths) and the consolidated openapi.{en,zh}.json (327 → 335 paths); EN/ZH files are structurally identical (same operationIds, schema keys, examples).
• docs.json: new Knowledge/知识 subgroup (icon book) in the AI SRE group of both language navs with all 8 POST /safari/knowledge/... entries.
• {en,zh}/openapi/api-catalog.mdx: new ### Knowledge/### 知识 table with 8 rows; AI SRE count 33 → 41, total 327 → 335.

Validation

• python3 json.load on all four spec files + docs.json — OK.
• Every spec path reachable from both the docs.json nav and both catalog pages (scripted check — no misses).
• EN/ZH twin parity check (same path keys, operationIds, schema keys) — OK.
• mint broken-links — no broken links found.