feat(skills): fall back to hub path when consumer submodule is stale

[WesleyMFrederick]

Problem

When the .claude submodule is behind the hub, skills that exist in the hub but not yet in the consumer cannot be invoked via the Skill tool. Claude has no fallback to read skills directly from the hub path.

Reproduction Steps

1. Hub adds new skills (e.g., git-sync-submodule-deterministic)
2. Consumer submodule is 25 commits behind — skill doesn't exist locally
3. User or Claude tries to invoke the skill via Skill tool
4. Skill tool fails: "Unknown skill"
5. Must manually read skill from hub path as a workaround

Root Cause

No CLAUDE.md rule or skill instructs Claude to fall back to the hub path when the Skill tool fails for a submodule-based project. The hub path is known (from MEMORY.md) but not used as a fallback.

Architecture Principles Violated

Baseline violates:

• ^foundation-reuse: Hub skills exist and are accessible via filesystem, but Claude doesn't leverage them when the consumer is stale.
• ^progressive-defaults: No fallback path for the 80% case (submodule drift is common). Requires manual intervention every time.
• ^error-recovery: Skill tool failure is terminal — no graceful fallback to alternative source.

Ideal incorporates:

• ^foundation-reuse: Use hub path (already in MEMORY.md) as fallback source for skills.
• ^progressive-defaults: Default to local submodule, fall back to hub path transparently.
• ^error-recovery: On Skill tool failure, read skill from hub and follow it.

Expected Behavior

When Skill tool returns "Unknown skill" in a submodule-based project, Claude reads the skill from the hub path and follows it.

Related

• MEMORY.md - hub path stored as cc-workflows-plugin location
• bug(skills): user's explicit skill invocation silently ignored due to scope conflict #17 - related skill invocation conflict
• bug(setup-worktree): stale submodule blocks creation, requires destructive sync #19 - stale submodule blocking worktree

Note

This is a CLAUDE.md rule addition, not a code change. The hub path is already known; just needs a fallback protocol.

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Acceptance Criteria

• CLAUDE.md or using-superpowers skill includes hub fallback protocol
• When Skill tool fails, Claude reads skill from hub path
• Hub path is resolved from MEMORY.md, not hardcoded
• Works for any submodule-based consumer project

Definition of Done

• Rule or skill updated
• Tested with subagent evaluation (invoke missing skill, verify fallback)
• Committed with conventional commit