Model Groups searchable picker and inline name editor

[grzegorznowak]

Summary

This PR improves Model Groups editing in two bounded places:

• the add-model wizard gains Pi-native fuzzy search and a ten-row scrolling viewport over the complete eligible model catalog; and
• the existing group-name Input is composed as one prompt-free inline Name: value row while retaining Pi's cursor, IME, Unicode-width, and editing behavior.

The inline editor is explicitly owned by operator-authorized feedback receipt FB-014, resolving the earlier SC-001 scope concern. Rename persistence and keyboard semantics are unchanged.

Original tickets

• Product baseline: Model Groups spawn router #14
• FB-014: restore the inline Model Groups name editor within this story/PR

Requirements

Searchable/capped add-model picker

• Fuzzy-search eligible models by model ID, provider, provider/model ID, or display name using Pi's public search primitive.
• Keep candidates limited to authenticated models from the selected provider.
• Show no more than ten model rows while the complete result set remains counted, scrollable, and selectable.
• Preserve exact raw provider/model identity independently from escaped, styled, or truncated labels.
• Retain the Provider → Model → Thinking flow, predictable query editing/back navigation, no-result safety, and query lifecycle behavior.

Inline group-name editor

• Render the inactive editor row as one logical Name: value row with no separate Pi > prompt or cursor artifact.
• While active, suppress only the literal Pi prompt and preserve exactly one real cursor/IME marker plus native editing and horizontal scrolling.
• Keep active and inactive rendering width-bounded for narrow terminals, wide Unicode, and combining graphemes.
• Preserve existing Enter, Esc, and row-change rename behavior: pending canonical edits flush once and established validation, persistence, and error handling remain intact.

Acceptance criteria

• The Model step exposes every eligible model, fuzzy-filters the complete set, and displays at most ten model rows.
• Results beyond the tenth remain reachable; filtered and offscreen selection persists exact registry identity.
• Query-value changes reset selection; cursor-only movement does not.
• No-match Enter/Up/Down is inert; nonempty-query Left/Backspace edits; empty-query Left/Backspace and Esc return to Provider.
• Returning from Thinking preserves the query; abandoning, completing, exiting, or reopening clears it.
• The group-name value appears on the same row as Name: both inactive and active, without a separate > prompt.
• The active name editor retains one cursor marker and remains bounded at widths 1, 2, and 12 with wide and combining Unicode.
• Enter, Esc, and row changes retain existing exact-once rename commit/error behavior.
• Other Model Groups screens receive no search or viewport behavior changes.
• No dependency, manifest, lockfile, schema, routing, spawn, or persistence-format changes are introduced.
• [Unreleased] contains one combined entry covering the picker and inline editor.

Contract changes

• The add-model wizard's Model step now provides fuzzy search and a ten-visible-row viewport over all eligible results.
• Model-step query navigation follows the empty/nonempty behavior described above.
• The existing group-name editor is presented inline; its persistence and keyboard contract is unchanged.

Out of scope

• Search or viewport changes outside the add-model wizard's Model step.
• Any EDITOR behavior change beyond FB-014's one-line group-name presentation.
• Changes to model authorization, validation, storage, routing, spawn behavior, or rename persistence.
• Custom fuzzy matching, first-ten-only truncation, manual list wrapping, or an additional wizard step.
• Dependency upgrades, manifest changes, or lockfile changes.
• Retroactive rewriting of the initiative, merged PR Model Groups spawn router #14, or historical SC-001 evidence.

How to verify

1. Open /model-groups, edit a group, and select Name:.
2. Confirm inactive and active states occupy one row, show no separate > prompt, and retain the native editing cursor while active.
3. Exercise typing, Left, Backspace, Enter, Esc, and row-change commits, including validation or persistence failures.
4. Confirm narrow widths and wide/combining Unicode remain bounded.
5. Open Add model and select a provider with more than ten authenticated models.
6. Search by model/provider/display fields, navigate beyond the tenth result, and select filtered/offscreen entries.
7. Verify query editing, no-match behavior, back navigation, and query preservation/reset boundaries.
8. Confirm other Model Groups screens retain their existing list behavior.
9. Confirm the combined [Unreleased] changelog entry.

Automated coverage includes 493 unit tests, 16 E2E tests, Pi 0.82.0 floor/current compatibility lanes, package-host smoke, typecheck, snapshots, and focused TAP-14/TAP-15 transition and rendering proofs.

Initiative reference

• Initiative: model-tag-router
• Story: model-groups-searchable-capped-picker
• Feedback: FB-014 (resume-current-story)
• Change workspace: openspec/changes/model-groups-searchable-capped-picker/

[ofriw]

LGTM