feat: Dynamic system prompt architecture with cortex-prompt-harness (#8)

* feat(prompt-harness): add dynamic tool injection support

- Add ToolDefinition struct to context.rs with name, description, and optional category
- Add tools field to PromptContext with add_tool() and with_tools() builder methods
- Add build_dynamic_tools_section() function to sections.rs for markdown table rendering
- Add with_tools() method to SystemPromptBuilder in builder.rs
- Export ToolDefinition from lib.rs
- Add comprehensive tests for all new functionality

Tools are rendered as markdown tables, grouped by category when provided.

* feat(prompt-harness): add CortexPromptBuilder for dynamic prompt construction

- Add individual section constants extracted from CORTEX_MAIN_PROMPT:
  - SECTION_HEADER, SECTION_PRIME_DIRECTIVES, SECTION_COGNITIVE_ARCHITECTURE
  - SECTION_FAILURE_PROTOCOL, SECTION_CODE_DISCIPLINE, SECTION_QUALITY_CHECKPOINTS
  - SECTION_TOOLKIT, SECTION_RESPONSE_PATTERNS, SECTION_ANTI_PATTERNS, SECTION_OUTPUT_FORMAT
  - SECTION_NAMES constant listing all section names

- Implement CortexPromptBuilder with fluent API:
  - new() creates builder with all default sections enabled
  - without_section() / with_section() to toggle sections
  - add_tool() / with_tools() to add custom tools to toolkit
  - with_custom_toolkit() to replace default toolkit entirely
  - add_custom_section() to append custom sections
  - is_section_enabled() / enabled_sections() for introspection
  - build() / build_with_token_estimate() for final output

- Keep CORTEX_MAIN_PROMPT unchanged for backward compatibility
- Add 24 comprehensive tests for the new builder
- Export new types from prompts module

* refactor(cortex-engine): use cortex-prompt-harness for system prompt

* chore: remove cortex_prompt.txt (now in cortex-prompt-harness)

- Remove cortex_prompt.txt from repository root
- Update documentation in core.rs to reflect new architecture
- System prompt is now centralized in cortex-prompt-harness crate

The prompt content is now the canonical source in:
cortex_prompt_harness::prompts::CORTEX_MAIN_PROMPT

Author: echobt

Cargo.lock

@@ -28,6 +28,7 @@ cortex-hooks-ext = { path = "../cortex-hooks", package = "cortex-hooks" }
 cortex-share = { path = "../cortex-share" }
 cortex-plugins-ext = { path = "../cortex-plugins", package = "cortex-plugins" }
 cortex-batch = { path = "../cortex-batch" }
+cortex-prompt-harness = { path = "../cortex-prompt-harness" }
 
 # New feature crates (Phase 2)
 cortex-ghost = { path = "../cortex-ghost" }

cortex_prompt.txt

@@ -16,7 +16,7 @@ pub enum SystemPromptError {
 
 pub type Result<T> = std::result::Result<T, SystemPromptError>;
 
-const DEFAULT_SYSTEM_PROMPT: &str = include_str!("../../../../cortex_prompt.txt");
+const DEFAULT_SYSTEM_PROMPT: &str = cortex_prompt_harness::prompts::CORTEX_MAIN_PROMPT;
 
 pub fn load_system_prompt(path: Option<&Path>) -> Result<String> {
     match path {

src/cortex-engine/Cargo.toml

@@ -4,8 +4,8 @@ use std::path::PathBuf;
 
 use crate::config::Config;
 
-/// System prompt for the Cortex Agent - loaded from cortex_prompt.txt
-pub(crate) const SYSTEM_PROMPT: &str = include_str!("../../../../cortex_prompt.txt");
+/// System prompt for the Cortex Agent - loaded from cortex-prompt-harness
+pub(crate) const SYSTEM_PROMPT: &str = cortex_prompt_harness::prompts::CORTEX_MAIN_PROMPT;
 
 /// Build the system prompt for the agent.
 pub fn build_system_prompt(config: &Config) -> String {