fix: implement or remove dead CLI stub

[norrietaylor]

Problem

The agentry registry list command prints "Not yet implemented" and exits. This is a dead stub that has been present since Phase 1. It should either be wired up or removed.

Proposed Solution

Implement agentry registry list to discover and list available workflows:

1. Scan workflows/ directory for .yaml files
2. Parse each workflow's identity block (name, version, description)
3. Print a formatted table to stdout

Example Output

NAME                VERSION  DESCRIPTION
code-review         1.0.0    Review pull request code changes for quality issues
triage              1.0.0    Classify and triage a software issue
bug-fix             1.0.0    Diagnose a reported bug and suggest a targeted fix
task-decompose      1.0.0    Break down a triaged issue into implementation tasks
planning-pipeline   1.0.0    Comprehensive issue planning pipeline
feature-implement   1.0.0    Implement a feature based on planning-pipeline output

Acceptance Criteria

• agentry registry list prints a table of discovered workflows
• Workflows are discovered from the workflows/ directory relative to CWD
• Each row shows name, version, and description from the workflow YAML
• The command exits 0 on success
• Remove the "Not yet implemented" stub

Source

Backlog item from Source Code Cleanup section.

[github-actions]

Agentry Issue Triage

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[github-actions]

Triage output: /home/runner/work/agentry/agentry/.agentry/runs/triage/output.json (file not found)

[github-actions]

Triage output: /home/runner/work/agentry/agentry/.agentry/runs/task-decompose/output.json (file not found)

[github-actions]

Triage output: /home/runner/work/agentry/agentry/.agentry/runs/triage/output.json (file not found)