feat(plugin-catalog): add desensitize (community, tools)

Chinese-context PII redaction. Adds one catalog entry pinning
yubingz/hermes-desensitize at 8ef2d22.

The gap this fills: the catalog has secret redaction (vaultknox: API keys,
tokens, passwords — a 28-pattern English key-format registry) and, as open
proposals, English/Western PII middleware (#102922) and document-scoped
anonymization (#102049). None of them recognize Chinese-language entities,
which are a different problem rather than a translation of the English one:

- Person names have no whitespace or capitalization boundary; the name is
  identifiable only by part-of-speech, not token shape.
- Company and institution names are marker-SUFFIXED (有限公司 / 研究院 /
  分行), so recognition keys off the tail with a variable-length run before it.
- Addresses are hierarchical and recursive across 省/市/区/县/街道.
- Magnitudes are written with the unit attached (3.5 亿元), so masking digits
  alone still leaks the scale.

Capabilities declared (verified against the pinned commit by loading it
through the real plugin loader against a temp HERMES_HOME — all four hooks
register, and provides_tools / provides_middleware are genuinely empty):

    provides_hooks: pre_llm_call, pre_api_request, transform_llm_output,
                    post_llm_call
    provides_tools: []
    requires_env: []

Design note for review: it uses the existing hook pair rather than
register_middleware("llm_request", ...) as in #102922. Hooks were sufficient
and need no new surface; if middleware is the preferred long-term seam for
message-rewriting plugins, that is worth settling before more plugins are
written against hooks. Raised in #118722.

The entry's description carries a Disclosure paragraph, following the
vaultknox precedent, covering the parts a reviewer should not have to
discover by reading the code: inbound messages and outbound replies are both
rewritten, placeholders are code-generated and can over-match, company names
are matched greedily (a modifier is absorbed into the placeholder),
magnitude masking drops the numeric value and fires only on configured
trigger words, and the placeholder mapping is memory-only.

Structural check: `python3 scripts/validate_plugin_catalog.py
plugin-catalog/desensitize.yaml` -> OK, 1 file(s) valid.

No contributors/emails file is needed: yflmq001@users.noreply.github.com is
already mapped.

Fixes #118722

plugin-catalog/desensitize.yaml

@@ -0,0 +1,34 @@
+name: desensitize
+repo: https://github.com/yubingz/hermes-desensitize
+sha: 8ef2d22bafff5754edb1bbafd969b67ab4a1c06d
+subdir: src/hermes_desensitize
+description: "Chinese-context desensitization for Hermes chats. Replaces PII and business-sensitive
+  entities — person names, company names, addresses, file paths, and magnitude figures — with
+  reversible placeholders before a message reaches the model, then restores them in the reply.
+  Two layers: an optional local/OpenAI-compatible LLM for semantic entity judgment, plus a
+  sub-millisecond regex fallback (phone, ID card, email, IP, path) that keeps the conversation
+  working when the model is unavailable. Disclosure — rewrites inbound user messages and outbound
+  assistant replies, so transcript content differs from what you typed; placeholders are
+  code-generated and may over-match (18-digit ID-card-shaped strings, names that collide with
+  the public-entity allowlist); company names are matched greedily and a modifier such as
+  原北京某某有限公司 is absorbed into the placeholder; magnitude masking drops the numeric
+  value and only fires on the configured trigger words, so a domain term absent from that list
+  is left unmasked without warning; the placeholder mapping is held in memory only and never
+  written to disk."
+maintainer: yubingz
+tier: community
+category: tools
+requires_hermes: ">=0.19"
+docs_url: https://github.com/yubingz/hermes-desensitize#readme
+version: "1.0.0"
+readme: true
+platforms: []
+capabilities:
+  provides_tools: []
+  provides_hooks:
+    - pre_llm_call
+    - pre_api_request
+    - transform_llm_output
+    - post_llm_call
+  provides_middleware: []
+  requires_env: []