feat: add panic tracking and logging with PanicTracker

- Implemented PanicTracker to log panics using tracing within a dedicated span.
- Introduced PanicInfo struct to capture panic details.
- Added tests for panic catching and hook restoration.

feat: implement token-bucket rate limiter

- Created RateLimiter to manage token consumption with configurable rates and burst capacity.
- Added methods for acquiring tokens and checking available tokens.
- Included tests for rate limiting behavior and token availability.

feat: add automatic retry with exponential backoff

- Developed retry function to handle transient errors with configurable retry strategies.
- Introduced RetryConfig for customizing retry behavior and jitter.
- Added tests for various retry scenarios and error handling.

feat: implement graceful shutdown coordination

- Created ShutdownManager to manage shutdown signals and task completion.
- Introduced ShutdownSignal for tasks to observe shutdown requests.
- Added tests for shutdown request handling and task draining.

feat: add timeout functionality for async operations

- Implemented with_timeout function to enforce execution time limits on futures.
- Created Timeout struct for wrapping futures with a deadline.
- Added tests for timeout behavior and error mapping.

crates/corex-cache/LICENSE-MIT

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2026 The corex Authors
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.