feat: add OpenCode/Codex outputs and update changelog (#104)

* Add OpenCode converter coverage and specs

* Add Codex target support and spec docs

* Generate Codex command skills and refresh spec docs

* Add global Codex install path

* fix: harden plugin path loading and codex descriptions

* feat: ensure codex agents block on convert/install

* docs: clarify target branch usage for review

* chore: prep npm package metadata and release notes

* docs: mention opencode and codex in changelog

* docs: update CLI usage and remove stale todos

* feat: install from GitHub with global outputs

docs/specs/codex.md

@@ -0,0 +1,59 @@
+# Codex Spec (Config, Prompts, Skills, MCP)
+
+Last verified: 2026-01-21
+
+## Primary sources
+
+```
+https://developers.openai.com/codex/config-basic
+https://developers.openai.com/codex/config-advanced
+https://developers.openai.com/codex/custom-prompts
+https://developers.openai.com/codex/skills
+https://developers.openai.com/codex/skills/create-skill
+https://developers.openai.com/codex/guides/agents-md
+https://developers.openai.com/codex/mcp
+```
+
+## Config location and precedence
+
+- Codex reads local settings from `~/.codex/config.toml`, shared by the CLI and IDE extension. citeturn2view0
+- Configuration precedence is: CLI flags → profile values → root-level values in `config.toml` → built-in defaults. citeturn2view0
+- Codex stores local state under `CODEX_HOME` (defaults to `~/.codex`) and includes `config.toml` there. citeturn4view0
+
+## Profiles and providers
+
+- Profiles are defined under `[profiles.<name>]` and selected with `codex --profile <name>`. citeturn4view0
+- A top-level `profile = "<name>"` sets the default profile; CLI flags can override it. citeturn4view0
+- Profiles are experimental and not supported in the IDE extension. citeturn4view0
+- Custom model providers can be defined with base URL, wire API, and optional headers, then referenced via `model_provider`. citeturn4view0
+
+## Custom prompts (slash commands)
+
+- Custom prompts are Markdown files stored under `~/.codex/prompts/`. citeturn3view0
+- Custom prompts require explicit invocation and aren’t shared through the repository; use skills to share or auto-invoke. citeturn3view0
+- Prompts are invoked as `/prompts:<name>` in the slash command UI. citeturn3view0
+- Prompt front matter supports `description:` and `argument-hint:`. citeturn3view0turn2view3
+- Prompt arguments support `$1`–`$9`, `$ARGUMENTS`, and named placeholders like `$FILE` provided as `KEY=value`. citeturn2view3
+- Codex ignores non-Markdown files in the prompts directory. citeturn2view3
+
+## AGENTS.md instructions
+
+- Codex reads `AGENTS.md` files before doing any work and builds a combined instruction chain. citeturn3view1
+- Discovery order: global (`~/.codex`, using `AGENTS.override.md` then `AGENTS.md`) then project directory traversal from repo root to CWD, with override > AGENTS > fallback names. citeturn3view1
+- Codex concatenates files from root down; files closer to the working directory appear later and override earlier guidance. citeturn3view1
+
+## Skills (Agent Skills)
+
+- A skill is a folder containing `SKILL.md` plus optional `scripts/`, `references/`, and `assets/`. citeturn3view3turn3view4
+- `SKILL.md` uses YAML front matter and requires `name` and `description`. citeturn3view3turn3view4
+- Required fields are single-line with length limits (name ≤ 100 chars, description ≤ 500 chars). citeturn3view4
+- At startup, Codex loads only each skill’s name/description; full content is injected when invoked. citeturn3view3turn3view4
+- Skills can be repo-scoped in `.codex/skills/` or user-scoped in `~/.codex/skills/`. citeturn3view4
+- Skills can be invoked explicitly using `/skills` or `$skill-name`. citeturn3view3
+
+## MCP (Model Context Protocol)
+
+- MCP configuration lives in `~/.codex/config.toml` and is shared by the CLI and IDE extension. citeturn3view2turn3view5
+- Each server is configured under `[mcp_servers.<server-name>]`. citeturn3view5
+- STDIO servers support `command` (required), `args`, `env`, `env_vars`, and `cwd`. citeturn3view5
+- Streamable HTTP servers support `url` (required), `bearer_token_env_var`, `http_headers`, and `env_http_headers`. citeturn3view5