refactor: streamline installer temp file usage and user messaging

- Replace use of TMPDIR with a dedicated GORUSH_TMPDIR for downloading and cleaning up temporary files
- Switch print_message calls to printf for clearer user messages after installation
- Optimize release version retrieval by storing the curl response and parsing locally, improving efficiency and reducing duplicate requests
- Condense shell checks when adding install dir to PATH into a single branch to avoid repetition
- Minor improvement to logging the checked config files variable

Signed-off-by: appleboy <appleboy.tw@gmail.com>

docs(readme): refactor and enhance redis configuration options

- Remove duplicate redis configuration block
- Add db option to redis configuration

Signed-off-by: appleboy <appleboy.tw@gmail.com>

refactor: harden gRPC server and test files for improved security

- Change file permissions for temporary test files from 644 to 600 for improved security
- Switch to using net.ListenConfig for gRPC server socket creation
- Remove an unused comment in the status engine initialization
- Define a redisEngine constant for test clarity and reuse, updating assignments accordingly

Signed-off-by: appleboy <appleboy.tw@gmail.com>

ci: enable Trivy scanning and exclude certificates directory

- Add Trivy configuration file with scan settings
- Exclude the certificate directory from vulnerability scanning

Signed-off-by: appleboy <appleboy.tw@gmail.com>

docs: update documentation and configuration for latest release

- Change changelog source from git to GitHub in `.goreleaser.yaml`
- Update download links in `README.md` to use gorush version 1.18.9
- Update Go version requirement in `README.md` to at least Go 1.22

Signed-off-by: appleboy <appleboy.tw@gmail.com>

fix: refactor codebase for improved architecture compatibility

- Change architecture identifier from `i386` to `386`

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

docs: enhance notification API documentation and examples

- Update Netlify link description and add Firebase Cloud Messaging web link
- Add example curl command for sending a notification via the API

Signed-off-by: appleboy <appleboy.tw@gmail.com>

chore(fcm): notification handling logic for sound field (#797)

* chore(fcm): notification handling logic for sound field

- Remove `IsGRPC` field from `PushNotification` struct
- Simplify condition by removing `IsGRPC` check in `GetAndroidNotification`
- Add checks for `APNS` and `Android` fields in `GetAndroidNotification`
- Remove `IsGRPC` initialization in `Send` method of `Server`

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

* refactor: refactor sound request handling and validation

- Change `req.Sound` type check from string to interface
- Add type assertion for `req.Sound` to string
- Ensure `req.APNS` and `req.Android` are only set if `req.Sound` is a string

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

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Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

feat: implement gRPC support sound field for FCM (#794)

- Add `IsGRPC` field to `PushNotification` struct
- Add logic to handle sound configuration for gRPC notifications in `GetAndroidNotification`
- Set `IsGRPC` to `true` in the `Send` function of the `Server` struct

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

refactor(fcm): test Android notification handling (#786)

- Refactor JSON marshaling logic in `GetAndroidNotification` function
- Add test case for JSON data structure in `TestAndroidNotificationStructure` function

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>