Feature: Restore recent discovery session and saved context

[sajeetharan]

Problem

Visitors lose their selected developer, filters, searches, and globe position when they refresh or return. Every session starts from scratch, which discourages deeper exploration.

Proposed solution

Persist non-sensitive discovery context locally and restore it through a clear Continue exploring entry point.

Acceptance criteria

• Persist recent searches, active filters, selected developer, comparison state, and globe viewpoint
• Restore context only when the referenced developer and filters remain valid
• Add a Continue exploring action rather than unexpectedly moving the globe on load
• Let users clear recent activity and disable local history
• Set bounded history size and expiration
• Do not store private profile fields, OAuth data, or raw search embeddings
• Handle schema changes and corrupted browser storage safely
• Track restoration offers and accepted restores without recording search contents
• Add tests for expiry, invalid entities, opt-out, and migration

Related issues

• Watchlists and notifications: Feature: Developer and project watchlists with update notifications #113
• Comparison: Compare developers side-by-side #23
• Live filters: Feature: Unified live filters panel for status, languages, editors, and platforms #91