Search: recent searches, clear button, and encoded addon search URLs

[silentbil]

Why

Search had no memory: every query had to be typed again with the remote keyboard, and once a query was in the bar there was no quick way to empty it. Separately, addon catalog search sent the catalog type and id unencoded, unlike every other catalog URL, so addons with types such as Live Docs got a broken request.

What changed

• Recent searches: the profile's last 8 queries appear as a chip row under the search bar while it is empty. A query is saved on submit or when a result is opened from it, and only if it found something (typing alone never saves). OK on a chip runs it immediately and moves focus into the results; a single Clear chip removes the whole list. Stored per profile.
• Clear button in the search bar while it holds a query: on TV, D-pad toward the end of the bar and press OK; on touch, tap the ×.
• D-pad: the recent row is its own focus stop between the search bar and the filter row (search → recent → filters → results), RTL-aware; when the row is cleared, focus moves on to the filters.
• Addon search URLs now use the shared path-segment encoder for type, id and query.

Testing

• Unit tests: full TV suite passing (2296), including new tests for saving rules, slot mapping, and the encoded search URL.
• Manually on an Android TV emulator: submit and open-result both save, the newest query comes first, running a recent query, Clear, the bar's clear button, and D-pad movement in RTL.