Read skills from .agents/skills and improve configurability

[zikajk]

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1. Codex, opencode, pi, copilot read the skills from .agents/skills (it is somewhat standard, see https://agentskills.io/home).

2. Current state

Feature	Config key	Accepts	Recursive directory?
Rules	rules: [{path: "..."}]	Single file only	❌
Commands	commands: [{path: "..."}]	Single file only	❌
Skills	—	Not configurable	—

Rules and commands in config.json only accept paths to individual files. There is no way to point them at a directory and have all files loaded recursively. This is inconsistent with how the file-based sources work (~/.config/eca/rules/** and .eca/rules/** both glob directories recursively).

Skills have no config.json representation at all — the only way to add skills from custom paths is via the plugin system (which populates an internal :pluginSkillDirs).

Proposal

1. Add skills: [{path: "..."}] to config.json, consistent with the existing rules and commands shape.
2. Support both files and directories in path for rules, commands, and skills:
   • If path points to a file → load it (current behavior)
   • If path points to a directory → recursively load all files matching the expected pattern (e.g. **/*.md for commands, **/SKILL.md for skills, ** for rules)

This gives users a uniform, simple way to point at a folder of rules/skills/commands from anywhere on disk without having to enumerate each file individually.

I initially thought it would be nice to have something like :extra-paths {:commands ..., :rules ..., :skills ...}, but that would be inconsistent and break backward compatibility, so I dropped the idea.

What do you think @ericdallo ?
I would work on this over the weekend.

[ericdallo]

Looks valid to me, feel free to work on that!
Would be nice to have a default config to read that .agents/skills, but I suppose you thought about that already