Add cache to dedupe table (which adds limit)

[NGTmeaty]

This should ensure that we don't grow infinitely 😅 Default is 1M which seems sane.

[Copilot]

Pull request overview

This pull request adds a bounded cache to the deduplication table to prevent unbounded memory growth. The implementation replaces the unbounded sync.Map with a bounded LRU cache from the github.com/maypok86/otter library, with a default size limit of 1 million entries.

Changes:

• Replaced sync.Map with otter.Cache[string, revisitRecord] for bounded deduplication storage
• Added DedupeCacheSize configuration option to DedupeOptions
• Updated API calls from Load/Store to type-safe Get/Set methods, eliminating type assertions
• Added proper cache cleanup in Close() method

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
client.go	Added otter cache import, changed dedupeHashTable type to otter.Cache, implemented cache initialization with default 1M size, added closeDedupeCache cleanup function
dedupe.go	Added DedupeCacheSize field to DedupeOptions, updated checkLocalRevisit to use type-safe Get() method, removed minor trailing whitespace
dialer.go	Updated Store call to Set for storing dedupe entries

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[willmhowes]

Looks good! Have one question, primarily for my own understanding