add documentation for ai agents (#3115)

* add documentation for ai agents

* docs: consolidate CLAUDE.md and CONTRIBUTING.md, add style guidelines

- Refactor CLAUDE.md to reference CONTRIBUTING.md for build/test/format info
- Expand CONTRIBUTING.md with comprehensive build targets, env vars, and testing
- Add code style guidelines section with conventional commits
- Standardize SDK prettier config to use single quotes (matching web)
- Add project-level Claude Code settings to disable co-author attribution

* style(sdk): apply prettier with single quotes

Run prettier across sdk/base and sdk/package to apply the
standardized quote style (single quotes matching web).

* docs: add USER.md for per-developer TODO filtering

- Add agents/USER.md to .gitignore (contains user identifier)
- Document session startup flow in CLAUDE.md:
  - Create USER.md if missing, prompting for identifier
  - Filter TODOs by @username tags
  - Offer relevant TODOs on session start

* docs: add i18n documentation task to agent TODOs

* docs: document i18n ID patterns in core/

Add agents/i18n-patterns.md covering rust-i18n setup, translation file
format, t!() macro usage, key naming conventions, and locale selection.
Remove completed TODO item and add reference in CLAUDE.md.

* chore: clarify that all builds work on any OS with Docker

agents/core-rust-patterns.md

@@ -0,0 +1,249 @@
+# Utilities & Patterns
+
+This document covers common utilities and patterns used throughout the StartOS codebase.
+
+## Util Module (`core/src/util/`)
+
+The `util` module contains reusable utilities. Key submodules:
+
+| Module | Purpose |
+|--------|---------|
+| `actor/` | Actor pattern implementation for concurrent state management |
+| `collections/` | Custom collection types |
+| `crypto.rs` | Cryptographic utilities (encryption, hashing) |
+| `future.rs` | Future/async utilities |
+| `io.rs` | File I/O helpers (create_file, canonicalize, etc.) |
+| `iter.rs` | Iterator extensions |
+| `net.rs` | Network utilities |
+| `rpc.rs` | RPC helpers |
+| `rpc_client.rs` | RPC client utilities |
+| `serde.rs` | Serialization helpers (Base64, display/fromstr, etc.) |
+| `sync.rs` | Synchronization primitives (SyncMutex, etc.) |
+
+## Command Invocation (`Invoke` trait)
+
+The `Invoke` trait provides a clean way to run external commands with error handling:
+
+```rust
+use crate::util::Invoke;
+
+// Simple invocation
+tokio::process::Command::new("ls")
+    .arg("-la")
+    .invoke(ErrorKind::Filesystem)
+    .await?;
+
+// With timeout
+tokio::process::Command::new("slow-command")
+    .timeout(Some(Duration::from_secs(30)))
+    .invoke(ErrorKind::Timeout)
+    .await?;
+
+// With input
+let mut input = Cursor::new(b"input data");
+tokio::process::Command::new("cat")
+    .input(Some(&mut input))
+    .invoke(ErrorKind::Filesystem)
+    .await?;
+
+// Piped commands
+tokio::process::Command::new("cat")
+    .arg("file.txt")
+    .pipe(&mut tokio::process::Command::new("grep").arg("pattern"))
+    .invoke(ErrorKind::Filesystem)
+    .await?;
+```
+
+## Guard Pattern
+
+Guards ensure cleanup happens when they go out of scope.
+
+### `GeneralGuard` / `GeneralBoxedGuard`
+
+For arbitrary cleanup actions:
+
+```rust
+use crate::util::GeneralGuard;
+
+let guard = GeneralGuard::new(|| {
+    println!("Cleanup runs on drop");
+});
+
+// Do work...
+
+// Explicit drop with action
+guard.drop();
+
+// Or skip the action
+// guard.drop_without_action();
+```
+
+### `FileLock`
+
+File-based locking with automatic unlock:
+
+```rust
+use crate::util::FileLock;
+
+let lock = FileLock::new("/path/to/lockfile", true).await?;  // blocking=true
+// Lock held until dropped or explicitly unlocked
+lock.unlock().await?;
+```
+
+## Mount Guard Pattern (`core/src/disk/mount/guard.rs`)
+
+RAII guards for filesystem mounts. Ensures filesystems are unmounted when guards are dropped.
+
+### `MountGuard`
+
+Basic mount guard:
+
+```rust
+use crate::disk::mount::guard::MountGuard;
+use crate::disk::mount::filesystem::{MountType, ReadOnly};
+
+let guard = MountGuard::mount(&filesystem, "/mnt/target", ReadOnly).await?;
+
+// Use the mounted filesystem at guard.path()
+do_something(guard.path()).await?;
+
+// Explicit unmount (or auto-unmounts on drop)
+guard.unmount(false).await?;  // false = don't delete mountpoint
+```
+
+### `TmpMountGuard`
+
+Reference-counted temporary mount (mounts to `/media/startos/tmp/`):
+
+```rust
+use crate::disk::mount::guard::TmpMountGuard;
+use crate::disk::mount::filesystem::ReadOnly;
+
+// Multiple clones share the same mount
+let guard1 = TmpMountGuard::mount(&filesystem, ReadOnly).await?;
+let guard2 = guard1.clone();
+
+// Mount stays alive while any guard exists
+// Auto-unmounts when last guard is dropped
+```
+
+### `GenericMountGuard` trait
+
+All mount guards implement this trait:
+
+```rust
+pub trait GenericMountGuard: std::fmt::Debug + Send + Sync + 'static {
+    fn path(&self) -> &Path;
+    fn unmount(self) -> impl Future<Output = Result<(), Error>> + Send;
+}
+```
+
+### `SubPath`
+
+Wraps a mount guard to point to a subdirectory:
+
+```rust
+use crate::disk::mount::guard::SubPath;
+
+let mount = TmpMountGuard::mount(&filesystem, ReadOnly).await?;
+let subdir = SubPath::new(mount, "data/subdir");
+
+// subdir.path() returns the full path including subdirectory
+```
+
+## FileSystem Implementations (`core/src/disk/mount/filesystem/`)
+
+Various filesystem types that can be mounted:
+
+| Type | Description |
+|------|-------------|
+| `bind.rs` | Bind mounts |
+| `block_dev.rs` | Block device mounts |
+| `cifs.rs` | CIFS/SMB network shares |
+| `ecryptfs.rs` | Encrypted filesystem |
+| `efivarfs.rs` | EFI variables |
+| `httpdirfs.rs` | HTTP directory as filesystem |
+| `idmapped.rs` | ID-mapped mounts |
+| `label.rs` | Mount by label |
+| `loop_dev.rs` | Loop device mounts |
+| `overlayfs.rs` | Overlay filesystem |
+
+## Other Useful Utilities
+
+### `Apply` / `ApplyRef` traits
+
+Fluent method chaining:
+
+```rust
+use crate::util::Apply;
+
+let result = some_value
+    .apply(|v| transform(v))
+    .apply(|v| another_transform(v));
+```
+
+### `Container<T>`
+
+Async-safe optional container:
+
+```rust
+use crate::util::Container;
+
+let container = Container::new(None);
+container.set(value).await;
+let taken = container.take().await;
+```
+
+### `HashWriter<H, W>`
+
+Write data while computing hash:
+
+```rust
+use crate::util::HashWriter;
+use sha2::Sha256;
+
+let writer = HashWriter::new(Sha256::new(), file);
+// Write data...
+let (hasher, file) = writer.finish();
+let hash = hasher.finalize();
+```
+
+### `Never` type
+
+Uninhabited type for impossible cases:
+
+```rust
+use crate::util::Never;
+
+fn impossible() -> Never {
+    // This function can never return
+}
+
+let never: Never = impossible();
+never.absurd::<String>()  // Can convert to any type
+```
+
+### `MaybeOwned<'a, T>`
+
+Either borrowed or owned data:
+
+```rust
+use crate::util::MaybeOwned;
+
+fn accept_either(data: MaybeOwned<'_, String>) {
+    // Use &*data to access the value
+}
+
+accept_either(MaybeOwned::from(&existing_string));
+accept_either(MaybeOwned::from(owned_string));
+```
+
+### `new_guid()`
+
+Generate a random GUID:
+
+```rust
+use crate::util::new_guid;
+
+let guid = new_guid();  // Returns InternedString
+```