Add project-local HK IPO skills

Request:
- Keep the HK IPO workflow skills inside the repo so they travel with the project.
- Use concise names while preserving clear HK IPO scope and repo-relative path rules.

Changes:
- Add .codex/skills/archivist for source archiving, SQLite fact updates, hashes, and CSV snapshots.
- Add .codex/skills/analyst for T0/T1/T2 IPO decisions, prediction cards, reviews, and rule-change recommendations.
- Add agents/openai.yaml metadata for both skills.

Verification:
- Checked staged changes include only .codex skill files.
- Searched .codex for machine-specific absolute path patterns; none found.

Next useful context:
- AGENTS.md remains untracked and was not included in this commit.

.codex/skills/archivist/SKILL.md

@@ -0,0 +1,82 @@
+---
+name: archivist
+description: Use for Hong Kong IPO fact archiving in this project: downloading or recording prospectuses, allotment results, listing facts, market data, source references, file hashes, SQLite updates, and CSV snapshots. Do not use for investment conclusions, subscription recommendations, score interpretation, or research memos.
+---
+
+# HK IPO Archivist
+
+## Purpose
+
+Maintain the project-local Hong Kong IPO evidence archive and structured fact database. This skill owns facts, sources, database updates, path hygiene, and reproducible snapshots.
+
+It does not decide whether an IPO is worth subscribing for. Route judgment, scoring, prediction cards, review cards, and reports to `analyst`.
+
+## Project Storage Contract
+
+Use repo-relative paths everywhere. Never store machine-specific absolute paths.
+
+- Resolve the repo root at runtime, for example with `git rev-parse --show-toplevel`.
+- Store paths without a leading `./`.
+- Store paths with POSIX separators, such as `data/raw/06658/prospectus.pdf`.
+- Store `path_base = "repo_root"` when a table needs an explicit base.
+- Store `file_sha256` for archived source files whenever practical.
+
+Expected project layout:
+
+```text
+data/
+  hk_ipo.sqlite
+  raw/
+  snapshots/
+memos/
+reports/
+rules/
+schema/
+scripts/
+references/
+```
+
+## Responsibilities
+
+- Archive primary source files under `data/raw/{ticker}/`.
+- Record source references, URLs, as-of timestamps, relative paths, and hashes.
+- Update embedded SQLite tables for IPO facts.
+- Export Git-friendly CSV snapshots after database updates.
+- Preserve raw source files; do not overwrite without first checking whether the contents changed.
+- Label missing, stale, inconsistent, or estimated fields explicitly.
+
+## Boundaries
+
+Do not write:
+
+- Subscription decisions.
+- Investment ratings.
+- Scoring interpretations.
+- Prediction cards.
+- Review conclusions.
+- Rule-change recommendations.
+
+If a user asks for both data update and analysis, complete the archive/update step first, then hand the frozen as-of dataset to `analyst`.
+
+## Workflow
+
+1. Inspect current repo state and recent commits before changing files.
+2. Identify the IPO ticker, company, stage, and source documents needed.
+3. Save raw source files under `data/raw/{ticker}/` using descriptive names.
+4. Compute hashes for archived files.
+5. Insert or update structured facts in `data/hk_ipo.sqlite`.
+6. Record every source in the source reference table using repo-relative paths.
+7. Export key tables to `data/snapshots/` for readable Git diffs.
+8. Verify path rules, required fields, and snapshot generation.
+9. Commit only the related archive/database/snapshot changes.
+
+## Quality Checks
+
+Before finishing, confirm:
+
+- No stored local path is absolute.
+- No stored local path starts with `./`.
+- Raw files referenced by the database exist.
+- Source hashes match current file contents.
+- CSV snapshots reflect the database update.
+- Any unavailable field is marked as a data gap rather than invented.