feat(context-keeper): Add session context persistence power

[logesh4v]

Summary

Adds Context Keeper — a Knowledge Base Power that preserves session context across Kiro chat windows using hooks and steering files.

What it does

• Auto-captures structured session summaries on agentStop (7-section format: decisions, files modified, patterns, preferences, next steps)
• Auto-restores prior context on promptSubmit (branch-aware, with fallback)
• Manual snapshot and compression via userTriggered hooks
• Persistent project memory that accumulates long-term knowledge across all sessions
• Branch-scoped context — restores prefer same-branch summaries
• 20-file rolling window with automatic cleanup

Structure

context-keeper/
├── POWER.md                        # Power metadata + onboarding
├── hooks/
│   ├── capture-context.kiro.hook   # agentStop → save session summary
│   ├── restore-context.kiro.hook   # promptSubmit → load prior context
│   ├── snapshot-context.kiro.hook  # userTriggered → manual save
│   └── compress-context.kiro.hook  # userTriggered → consolidate old summaries
└── steering/
    ├── capture-context.md
    ├── restore-context.md
    ├── snapshot-context.md
    ├── project-memory-update.md
    └── compress-context.md

• Pattern C (Knowledge Base Power) — no MCP server
• 4 hooks + 5 steering files
• Zero external dependencies

Testing

• Tested locally via Powers panel "Add Custom Power"
• All hooks fire correctly on their respective events
• Branch-scoped context restore works as expected
• Standalone GitHub repo: https://github.com/logesh4v/context-keeper
• Also submitted via https://kiro.dev/powers/submit/

Why this power?

Context loss between sessions is one of the most reported pain points for Kiro users (see issues #5479, #1279, #2431). This power solves it with zero configuration — install and forget.

[github-actions]

Hi @logesh4v, thank you for your contribution!

Please note that if you haven't already, you would also need to submit your power officially at kiro.dev/powers/submit so it can be reviewed for listing in the Kiro powers registry.