Update installer system for update approval functionality

Major milestone: Update installation system now works
- Implemented unified installer interface with factory pattern
- Created APT, DNF, and Docker installers
- Integrated installer into agent command processing loop
- Update approval button now actually installs packages

Documentation updates:
- Updated claude.md with Session 7 implementation log
- Created clean, professional README.md for GitHub
- Added screenshots section with 4 dashboard views
- Preserved detailed development history in backup files

Repository ready for GitHub alpha release with working installer functionality.

aggregator-server/internal/database/migrations/003_create_update_tables.sql

@@ -0,0 +1,80 @@
+-- Event sourcing table for all update events
+CREATE TABLE IF NOT EXISTS update_events (
+    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    agent_id UUID NOT NULL REFERENCES agents(id) ON DELETE CASCADE,
+    package_type VARCHAR(50) NOT NULL,
+    package_name TEXT NOT NULL,
+    version_from TEXT,
+    version_to TEXT NOT NULL,
+    severity VARCHAR(20) NOT NULL CHECK (severity IN ('critical', 'important', 'moderate', 'low')),
+    repository_source TEXT,
+    metadata JSONB DEFAULT '{}',
+    event_type VARCHAR(20) NOT NULL CHECK (event_type IN ('discovered', 'updated', 'failed', 'ignored')),
+    created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW()
+);
+
+-- Current state table for optimized queries
+CREATE TABLE IF NOT EXISTS current_package_state (
+    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    agent_id UUID NOT NULL REFERENCES agents(id) ON DELETE CASCADE,
+    package_type VARCHAR(50) NOT NULL,
+    package_name TEXT NOT NULL,
+    current_version TEXT NOT NULL,
+    available_version TEXT,
+    severity VARCHAR(20) NOT NULL CHECK (severity IN ('critical', 'important', 'moderate', 'low')),
+    repository_source TEXT,
+    metadata JSONB DEFAULT '{}',
+    last_discovered_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+    last_updated_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+    status VARCHAR(20) NOT NULL DEFAULT 'pending' CHECK (status IN ('pending', 'approved', 'updated', 'failed', 'ignored', 'installing')),
+    UNIQUE(agent_id, package_type, package_name)
+);
+
+-- Version history table for audit trails
+CREATE TABLE IF NOT EXISTS update_version_history (
+    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    agent_id UUID NOT NULL REFERENCES agents(id) ON DELETE CASCADE,
+    package_type VARCHAR(50) NOT NULL,
+    package_name TEXT NOT NULL,
+    version_from TEXT NOT NULL,
+    version_to TEXT NOT NULL,
+    severity VARCHAR(20) NOT NULL CHECK (severity IN ('critical', 'important', 'moderate', 'low')),
+    repository_source TEXT,
+    metadata JSONB DEFAULT '{}',
+    update_initiated_at TIMESTAMP WITH TIME ZONE,
+    update_completed_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+    update_status VARCHAR(20) NOT NULL CHECK (update_status IN ('success', 'failed', 'rollback')),
+    failure_reason TEXT
+);
+
+-- Batch processing tracking
+CREATE TABLE IF NOT EXISTS update_batches (
+    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    agent_id UUID NOT NULL REFERENCES agents(id) ON DELETE CASCADE,
+    batch_size INTEGER NOT NULL,
+    processed_count INTEGER DEFAULT 0,
+    failed_count INTEGER DEFAULT 0,
+    status VARCHAR(20) NOT NULL DEFAULT 'processing' CHECK (status IN ('processing', 'completed', 'failed', 'cancelled')),
+    error_details JSONB DEFAULT '{}',
+    created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+    completed_at TIMESTAMP WITH TIME ZONE
+);
+
+-- Create indexes for performance
+CREATE INDEX IF NOT EXISTS idx_agent_events ON update_events(agent_id);
+CREATE INDEX IF NOT EXISTS idx_package_events ON update_events(package_name, package_type);
+CREATE INDEX IF NOT EXISTS idx_severity_events ON update_events(severity);
+CREATE INDEX IF NOT EXISTS idx_created_events ON update_events(created_at);
+
+CREATE INDEX IF NOT EXISTS idx_agent_state ON current_package_state(agent_id);
+CREATE INDEX IF NOT EXISTS idx_package_state ON current_package_state(package_name, package_type);
+CREATE INDEX IF NOT EXISTS idx_severity_state ON current_package_state(severity);
+CREATE INDEX IF NOT EXISTS idx_status_state ON current_package_state(status);
+
+CREATE INDEX IF NOT EXISTS idx_agent_history ON update_version_history(agent_id);
+CREATE INDEX IF NOT EXISTS idx_package_history ON update_version_history(package_name, package_type);
+CREATE INDEX IF NOT EXISTS idx_completed_history ON update_version_history(update_completed_at);
+
+CREATE INDEX IF NOT EXISTS idx_agent_batches ON update_batches(agent_id);
+CREATE INDEX IF NOT EXISTS idx_batch_status ON update_batches(status);
+CREATE INDEX IF NOT EXISTS idx_created_batches ON update_batches(created_at);