Integrate core functionality for tools, MCP, and enhanced session management

Adds consent management for tool execution, input validation, sandboxed process execution, and MCP server integration. Updates session management to support tool use, conversation persistence, and streaming responses.

Major additions:
- Database migrations for conversations and secure storage
- Encryption and credential management infrastructure
- Extensible tool system with code execution and web search
- Consent management and validation systems
- Sandboxed process execution
- MCP server integration

Infrastructure changes:
- Module registration and workspace dependencies
- ToolCall type and tool-related Message methods
- Privacy, security, and tool configuration structures
- Database-backed conversation persistence
- Tool call tracking in conversations

Provider and UI updates:
- Ollama provider updates for tool support and new Role types
- TUI chat and code app updates for async initialization
- CLI updates for new SessionController API
- Configuration documentation updates
- CHANGELOG updates

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

crates/owlen-core/src/validation.rs

@@ -0,0 +1,108 @@
+use std::collections::HashMap;
+
+use anyhow::{Context, Result};
+use jsonschema::{JSONSchema, ValidationError};
+use serde_json::{json, Value};
+
+pub struct SchemaValidator {
+    schemas: HashMap<String, JSONSchema>,
+}
+
+impl Default for SchemaValidator {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl SchemaValidator {
+    pub fn new() -> Self {
+        Self {
+            schemas: HashMap::new(),
+        }
+    }
+
+    pub fn register_schema(&mut self, tool_name: &str, schema: Value) -> Result<()> {
+        let compiled = JSONSchema::compile(&schema)
+            .map_err(|e| anyhow::anyhow!("Invalid schema for {}: {}", tool_name, e))?;
+
+        self.schemas.insert(tool_name.to_string(), compiled);
+        Ok(())
+    }
+
+    pub fn validate(&self, tool_name: &str, input: &Value) -> Result<()> {
+        let schema = self
+            .schemas
+            .get(tool_name)
+            .with_context(|| format!("No schema registered for tool: {}", tool_name))?;
+
+        if let Err(errors) = schema.validate(input) {
+            let error_messages: Vec<String> = errors.map(format_validation_error).collect();
+
+            return Err(anyhow::anyhow!(
+                "Input validation failed for {}: {}",
+                tool_name,
+                error_messages.join(", ")
+            ));
+        }
+
+        Ok(())
+    }
+}
+
+fn format_validation_error(error: ValidationError) -> String {
+    format!("Validation error at {}: {}", error.instance_path, error)
+}
+
+pub fn get_builtin_schemas() -> HashMap<String, Value> {
+    let mut schemas = HashMap::new();
+
+    schemas.insert(
+        "web_search".to_string(),
+        json!({
+            "type": "object",
+            "properties": {
+                "query": {
+                    "type": "string",
+                    "minLength": 1,
+                    "maxLength": 500
+                },
+                "max_results": {
+                    "type": "integer",
+                    "minimum": 1,
+                    "maximum": 10,
+                    "default": 5
+                }
+            },
+            "required": ["query"],
+            "additionalProperties": false
+        }),
+    );
+
+    schemas.insert(
+        "code_exec".to_string(),
+        json!({
+            "type": "object",
+            "properties": {
+                "language": {
+                    "type": "string",
+                    "enum": ["python", "javascript", "bash", "rust"]
+                },
+                "code": {
+                    "type": "string",
+                    "minLength": 1,
+                    "maxLength": 10000
+                },
+                "timeout": {
+                    "type": "integer",
+                    "minimum": 1,
+                    "maximum": 300,
+                    "default": 30
+                }
+            },
+            "required": ["language", "code"],
+            "additionalProperties": false
+        }),
+    );
+
+    schemas
+}