feat(skills): align with Agent Skills spec

[hannesrudolph]

Summary

Align Roo's Agent Skills implementation with the official Agent Skills specification (https://agentskills.io/specification) so we can be listed as a supported tool.

Spec coverage (frontmatter fields)

Table adapted from the official specification docs.

Field	Required	Constraints (per spec)	Before	After	Notes
name	Yes	Max 64 characters. Lowercase letters, numbers, and hyphens only. Must not start or end with a hyphen. Must not contain consecutive hyphens (--). Must match the parent directory name.	⚠️	✅	After: strictly validated during discovery in SkillsManager.
description	Yes	Max 1024 characters. Non-empty. Describes what the skill does and when to use it.	⚠️	✅	After: strictly validated during discovery in SkillsManager.
license	No	License name or reference to a bundled license file.	❌	❌	Not parsed/stored today.
compatibility	No	Max 500 characters. Environment requirements.	❌	❌	Not parsed/stored today.
metadata	No	Arbitrary key-value mapping.	❌	❌	Not parsed/stored today.
allowed-tools	No	Space-delimited list of pre-approved tools. (Experimental)	❌	❌	Not parsed/stored today.

Legend: ✅ implemented, ❌ not implemented, ⚠️ partially implemented (accepted non-spec values / not strict)

Changes

Spec alignment (⚠️ → ✅ in the table above)

• Enforce strict spec validation for skill name during discovery (1–64 chars; lowercase alnum + hyphens; no leading/trailing hyphen; no consecutive hyphens; must match directory name).
• Enforce strict spec validation for skill description during discovery (trimmed, non-empty; max 1024 chars).

Implementation improvements

• Emit <available_skills> XML in the prompt section (with proper XML escaping).
• Use absolute SKILL.md paths in <location> for filesystem-based agents.
• Add/expand automated tests covering prompt XML output + strict validation behavior.

[roomote]

Oroocle   See task on Roo Cloud

Re-review complete. No new issues found in the latest update.

• In src/core/prompts/sections/skills.ts: switch to a type-only import and drop the unused SkillMetadata import.

Previous reviews

• d993201: Review #1
• 5551bba: Review #2
• c824ccb: Review #3

_{Mention @roomote in a comment to request specific changes to this pull request or fix all unresolved issues.}

[mrubens]

Looks good aside from roomote’s comment