bug: users with multiple purchased identities cannot switch active handle — only first shown

[Al629176]

Bug: Users with multiple purchased identities can only see the first as their handle — no way to switch

Epic: #4190 — Tiny Place

Observed behaviour:
When a user has registered more than one identity/handle on Tiny Place, only the first purchased identity is shown as their active handle. There is no UI option to view, select, or switch between the other purchased identities.

Expected behaviour:

• All purchased identities should be listed in the Registry tab
• Users should be able to designate any of their purchased identities as their active handle
• The active handle should be reflected across the app (feed posts, profile, directory)

Root cause areas to investigate:

• Is tinyplace_identities_list RPC returning all identities or only the first?
• Is the UI reading only identities[0] instead of the full array?
• Is there an "active identity" concept in the backend? If not, it needs to be added
• The "set active identity" RPC may not exist yet — check src/openhuman/tinyplace/manifest.rs for an identities_set_active handler

Labels: bug, P1, tinyplace

[Al629176]

Part of epic #4190 — Tiny Place.