Initial scaffold: GyanDoot v2.0 in Rust

Full Cargo workspace with 11 crates:
- gyandoot-core: Shared types, config, error types
- gyandoot-agent: Agent loop, tool execution, context compression
- gyandoot-providers: LLM provider abstraction (OpenAI, Anthropic, Ollama)
- gyandoot-memory: MemPalace persistent memory system
- gyandoot-platform: Platform adapters (Telegram, Discord, Webhook, CLI)
- gyandoot-security: Credential vault, sanitizer, threat detector
- gyandoot-kanban: Task decomposition, swarm orchestration, diagnostics
- gyandoot-subagents: Sub-agent spawning and orchestration
- gyandoot-skills: Skills discovery, loading, preprocessing, bundles
- gyandoot-profile: Multi-agent profile manager
- gyandoot-gateway: Gateway sessions, routing, access control

Plus: CLI entry point with clap, cross-platform installer script,
KANBAN.md, .gnpl/AGENTS.md

Workspace compiles clean: cargo check passes with 0 errors.

crates/gyandoot-providers/src/lib.rs

@@ -0,0 +1,34 @@
+//! GyanDoot Providers — LLM provider abstraction layer.
+//!
+//! Defines the `Provider` trait and implementations for OpenAI, Anthropic,
+//! and Ollama. Each provider handles authentication, request formatting,
+//! response parsing, and streaming.
+
+use async_trait::async_trait;
+use gyandoot_core::{ConversationContext, ProviderResult};
+
+pub mod openai;
+pub mod anthropic;
+pub mod ollama;
+pub mod streaming;
+
+/// A provider response containing the generated text and any tool calls.
+#[derive(Debug, Clone)]
+pub struct ProviderResponse {
+    pub content: String,
+    pub tool_calls: Option<Vec<gyandoot_core::ToolCall>>,
+    pub finish_reason: String,
+}
+
+/// The trait that all LLM providers must implement.
+#[async_trait]
+pub trait Provider: Send + Sync {
+    /// Send a chat completion request and return the response.
+    async fn chat(&self, context: ConversationContext) -> ProviderResult<ProviderResponse>;
+
+    /// Send a chat completion request with streaming response.
+    async fn chat_stream(
+        &self,
+        context: ConversationContext,
+    ) -> ProviderResult<Box<dyn tokio_stream::Stream<Item = ProviderResult<String>> + Send + Unpin>>;
+}