Prefix HK IPO skill names

Request:
- Prefix the three selected project-local skill names with hk-ipo-.

Changes:
- Renamed skill metadata to hk-ipo-analyst, hk-ipo-archivist, and hk-ipo-audit.
- Updated skill-to-skill routing references to use the new names.
- Updated existing OpenAI skill UI metadata/default prompts for analyst and archivist.
- Updated README skill names and documented the audit skill.

Verification:
- Ran git diff --check and git diff --cached --check.
- Validated all local SKILL.md frontmatter names contain hk-ipo-.
- Confirmed README and current skill metadata have no old $analyst/$archivist/$audit invocations; old names remain only in historical reports.

README.md

@@ -36,7 +36,7 @@ The default exit discipline is T2/D1. D5/D20/D60 outcomes are kept to review whe
 
 This repository includes project-local Codex skills under `.codex/skills/`.
 
-### `archivist`
+### `hk-ipo-archivist`
 
 Owns facts and source control:
 
@@ -47,7 +47,7 @@ Owns facts and source control:
 
 It does not make investment recommendations.
 
-### `analyst`
+### `hk-ipo-analyst`
 
 Owns IPO judgment and review:
 
@@ -60,6 +60,17 @@ Owns IPO judgment and review:
 
 It should use archived facts when available and keep prediction cards append-only.
 
+### `hk-ipo-audit`
+
+Owns independent quality review:
+
+- check archive completeness and source integrity;
+- verify stage-appropriate evidence;
+- test analysis self-consistency;
+- identify blocking data gaps before rule or report changes.
+
+It does not archive new facts or make investment recommendations.
+
 ## Storage Model
 
 The project is intended to be self-contained and portable across machines. Durable paths should always be relative to the repository root.