Remove the retention question from onboarding; pathway defaults (30d team / 120d local)

[philcunliffe]

What

Removes the "Cache retention (days)" question from interactive onboarding. The wizard's pathway fork now decides the retention default instead of asking:

• Join a team (and a managed machine's scoped re-entry): 30 days - the org server holds the durable copy of forwarded history, so the local cache is a working window.
• Local install: 120 days - nothing leaves the machine, so the local cache is the only copy of history.

hyp init --retention-days <n> is unchanged (flag default stays 30) and remains the explicit override, as does editing query.cache.retention in the written config.

How

• wizard/index.js passes retentionDefault: LOCAL_INSTALL_RETENTION_DAYS (new, 120) to the pick phase only on the local pathway; team/scoped runs fall through to the pick phase's 30-day DEFAULT_RETENTION_DAYS.
• wizard/pick.js no longer prompts: retentionDays = opts.retentionDefault ?? DEFAULT_RETENTION_DAYS.
• walkthrough.js deletes the retention prompt factories (TUI text input + legacy readline) and the retentionPrompt/AsyncRetentionPrompt seams; the superseded programmatic walkthrough keeps the flat 30-day default without prompting.

Docs

• Mints LLP 0137 (onboarding-retention-defaults.decision.md, Active) with the choice and rationale; @ref LLP 0137#pathway-defaults annotations at the three code sites.
• Amends LLP 0011's walkthrough transcript and "Autodetect vs default" prose.

Tests

• New: pick-phase retention default coverage (30 without override, 120 via retentionDefault, pre-baked picks win) and orchestrator threading assertions (local passes 120, team passes nothing).
• Updated: dropped the injected retention prompts and scripted keystrokes for the removed question across 7 test files.
• npm test (2639 pass), npm run typecheck clean; smokes walkthrough_picker_to_first_query and walkthrough_backfill_client_history green. walkthrough_to_first_query fails identically on unmodified master on this machine (missing capture row, unrelated).

🤖 Generated with Claude Code

[philcunliffe]

neutral review (adopted PR, full-heal authorized) - reviewed at head 36d3aa0

Verdict: CLEAN. No actionable findings. Held for the maintainer to merge (neutral does not ready/merge a contributor PR).

What the change does

Removes the free-text "Cache retention (days)" question from onboarding (LLP 0137, amends LLP 0011) and replaces the flat 30-day default with a pathway-scoped default: 30 days on team/scoped installs, 120 days on local-only installs.

Correctness - verified end to end

• Pathway wiring is correct. runInitWizard (src/core/cli/wizard/index.js:135) passes retentionDefault: LOCAL_INSTALL_RETENTION_DAYS (120) only when pathway === 'local'; team and scoped omit the override and fall through to the pick phase's DEFAULT_RETENTION_DAYS (30). This matches LLP 0137's rule that scoped re-entry counts as the team side (30d).
• Pick phase applies it correctly. runWizardPick (src/core/cli/wizard/pick.js:156) sets retentionDays = opts.retentionDefault ?? DEFAULT_RETENTION_DAYS, and the value flows into composePickerConfig -> query.cache.retention.default_days, so persisted config and daemon get a valid value on both pathways.
• No stranded consumer of the removed answer. Grep confirms zero residual references to retentionPrompt / AsyncRetentionPrompt / the removed factories across src/, test/, hypaware-core/, bin/. Types (AsyncRetentionPrompt, retentionPrompt) and factories (tuiRetentionPromptFactory, legacyRetentionPromptFactory, defaultRetentionPromptFactory) are all removed cleanly. The text TUI import was dropped from walkthrough.js and is unused elsewhere; readline is still used by the surviving numbered-prompt factories.
• Non-interactive override intact. hyp init --retention-days <n> still flows through flags.retentionDays -> picks.retentionDays (src/core/commands/init.js:278, flag default 30). When picks is set, pick phase reads picks.retentionDays, which takes precedence over retentionDefault - covered by the "pre-baked picks override retentionDefault" test.
• Legacy runPickerWalkthrough (no pathway fork) keeps the flat 30-day default, as LLP 0137 documents.
• Back-compat: existing installs are untouched (retention lives in editable config, query.cache.retention); no migration needed.

Tests - updated and adequate

New/updated coverage in test/core/cli/wizard/{index,pick}.test.js: local pathway -> retentionDefault === 120; team pathway -> undefined (30d default); interactive run takes 30 without a prompt; retentionDefault: 120 lands 120 in the composed+written config; pre-baked picks override retentionDefault. Walkthrough/TUI/backfill/detect/init-guard tests updated to drop the removed retentionPrompt seam and assert the retention question is no longer rendered.

Style / LLP

No semicolons, no U+2014 em dashes in the changed files. @import JSDoc types used. @ref LLP 0137#pathway-defaults annotations are honest and the pathway-defaults anchor exists in the new LLP 0137; cross-doc references (0011#autodetect-vs-default, 0013#retention-is-the-central-tradeoff, 0031#open-questions--deferred) resolve to real heading-slug anchors. LLP 0011 correctly amended and LLP 0137 added.

Checks run (worktree, node_modules linked from main)

• Affected suites (wizard index/pick, walkthrough prompt/detect/tui-happy/backfill, init-guard): 59 tests, 59 pass, 0 fail.
• npm run typecheck (tsc --noEmit): clean.
• Known-unrelated test/core/leave-command.test.js failures not in scope.

No code changes were needed; nothing pushed to the branch.