Move SessionFs ADR out of public crate

ADR 0001 (SessionFsProvider trait and plumbing) captured the design
rationale for choosing direct Arc<dyn SessionFsProvider> registration
over the factory-closure pattern that Node/Python/Go use. That
rationale is internal release-engineering history, not consumer-facing
API documentation; the README's "Differences From Other SDKs" section
already explains what consumers need to know about the divergence.

The full ADR is being relocated to the private SDK release-plan
documentation in github/github-app PR #3166 (docs/copilot/2026-04-14-sdk-release/).

- Delete rust/docs/ entirely (only contained ADR 0001 + index README).
- Strip ADR links from rustdoc, README, CHANGELOG, and the
  session_fs example. The README's existing inline rationale (factory
  pattern doesn't cleanly express in Rust at the session-config call
  site, no `Session` value to thread in, SDK already prefers traits
  over closures for handler-shaped APIs) is sufficient on its own.

cargo doc -D warnings clean. cargo clippy clean. cargo fmt clean.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: tclem

rust/CHANGELOG.md

@@ -274,8 +274,7 @@ public surface.
   so providers only override the methods they need and forward-compatible
   schema additions land without breaking existing implementations.
   Diverges from Node/Python/Go's factory-closure pattern in favor of
-  direct `Arc<dyn SessionFsProvider>` registration — see
-  `docs/adr/0001-session-fs-provider.md` for the rationale.
+  direct `Arc<dyn SessionFsProvider>` registration.
 - W3C Trace Context propagation: new [`TraceContext`] struct and
   [`TraceContextProvider`] async trait in `crate::trace_context` (also
   re-exported from `crate::types`). Hybrid shape combines Node's

rust/README.md

@@ -520,10 +520,7 @@ ergonomics the dynamically-typed SDKs don't.
   cleanly express in Rust at the session-config call site — there is no
   `Session` value to thread in, and the SDK already prefers traits over
   boxed closures for handler-shaped APIs (`SessionHandler`, `SessionHooks`,
-  `ToolHandler`). See
-  [`docs/adr/0001-session-fs-provider.md`](docs/adr/0001-session-fs-provider.md)
-  for the full design rationale, including the rejected factory variant
-  and a forward-compat escape hatch.
+  `ToolHandler`).
 
 ```rust,ignore
 use std::sync::Arc;

rust/docs/adr/0001-session-fs-provider.md

@@ -5,11 +5,6 @@
 //! sessions, projecting files into virtual storage, or applying permission
 //! policies before bytes are read or written.
 //!
-//! See `docs/adr/0001-session-fs-provider.md` for the design rationale,
-//! including why this SDK uses direct `Arc<dyn SessionFsProvider>`
-//! registration rather than the factory-closure pattern used by the Node,
-//! Python, and Go SDKs.
-//!
 //! ```sh
 //! cargo run -p github-copilot-sdk --example session_fs
 //! ```

rust/docs/adr/README.md

@@ -356,7 +356,6 @@ pub struct ClientOptions {
     /// the CLI. Each session created on this client must supply its own
     /// [`SessionFsProvider`] via
     /// [`SessionConfig::with_session_fs_provider`](crate::SessionConfig::with_session_fs_provider).
-    /// See `docs/adr/0001-session-fs-provider.md`.
     pub session_fs: Option<SessionFsConfig>,
     /// Optional [`TraceContextProvider`] used to inject W3C Trace Context
     /// headers (`traceparent` / `tracestate`) on outbound `session.create`,

rust/examples/session_fs.rs

@@ -6,11 +6,6 @@
 //! applications sandbox sessions, project files into in-memory or remote
 //! storage, and apply permission policies before bytes move.
 //!
-//! See `rust/docs/adr/0001-session-fs-provider.md` for the full design
-//! rationale, including why this SDK uses direct `Arc<dyn SessionFsProvider>`
-//! registration rather than the factory-closure pattern used by Node, Python,
-//! and Go.
-//!
 //! # Concurrency
 //!
 //! Each inbound `sessionFs.*` request is dispatched on its own spawned task,

rust/src/lib.rs

@@ -767,7 +767,7 @@ pub struct SessionConfig {
     /// Custom session filesystem provider for this session. Required when
     /// the [`Client`](crate::Client) was started with
     /// [`ClientOptions::session_fs`](crate::ClientOptions::session_fs) set.
-    /// See [`SessionFsProvider`] and `docs/adr/0001-session-fs-provider.md`.
+    /// See [`SessionFsProvider`].
     #[serde(skip)]
     pub session_fs_provider: Option<Arc<dyn SessionFsProvider>>,
     /// Session-level event handler. The default is