chore(node-client-sdk): adding ability to override storage implementation

[joker23]

This PR will add storage option, which takes in an implementation of the LDStorage interface. When this option is present, we will ignore localStoragePath option and wholesale replace the default storage implementation.

We also considered introducing the storage option as a discriminated union eg { type: "custom", implementation: <storage impl> } and { type: "local", path: "." }, but I decided against it as having a flat option like this is easier to understand/interact with in my opinion.

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Note

Medium Risk
Custom storage affects persistent flag/cache behavior across SDK instances; misconfiguration or failing backends are mitigated by safe storage but still change runtime semantics. The unrelated sdkVersion bump in NodeInfo may affect telemetry/version reporting.

Overview
Adds a storage option on the Node client SDK so apps can plug in a custom LDStorage (get / set / clear) for the flag and anonymous-key cache. NodePlatform uses createSafeStorage when storage is set; otherwise it keeps the file-backed NodeStorage. Setting both localStoragePath and storage logs a warning and localStoragePath is ignored.

Option validation now checks storage shape, localStoragePath typing, and defaults useMobileKey to false, with a hard error if useMobileKey and secure-mode hash are both set. Public API docs for localStoragePath / storage are updated; resetNodeStorage is no longer exported from the package entry.

Tests cover custom storage wiring, safe-storage error handling, and the new validation rules. The diff also changes the embedded SDK version string in NodeInfo (0.0.4 → 0.0.1).

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[github-actions]

@launchdarkly/js-sdk-common size report
This is the brotli compressed size of the ESM build.
Compressed size: 26365 bytes
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Uncompressed size: 129044 bytes

[github-actions]

@launchdarkly/js-client-sdk-common size report
This is the brotli compressed size of the ESM build.
Compressed size: 38739 bytes
Compressed size limit: 39000
Uncompressed size: 212244 bytes

[github-actions]

@launchdarkly/js-client-sdk size report
This is the brotli compressed size of the ESM build.
Compressed size: 31978 bytes
Compressed size limit: 34000
Uncompressed size: 114243 bytes

[github-actions]

@launchdarkly/browser size report
This is the brotli compressed size of the ESM build.
Compressed size: 179579 bytes
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Uncompressed size: 831422 bytes

[joker23]

This is not wired yet and will come in the next PR. But would like some early feedback here if we do not think we should also support mobile keys.

[joker23]

@cursor review

[joker23]

@cursor review

[cursor]

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