Phase 3 command consolidation: 64 → ~40 slash commands

[BunsDev]

Phase 2 (#59, landed via #68 + #71) folded the config/usage/rewind clusters and removed the dead ide command, leaving 64 visible slash commands (PROMPT_SLASH_COMMANDS minus typeahead-only aliases). The ~40 target from docs/AUDIT-2026-06.md §4 needs roughly 24 more cuts. Proposed disposition matrix below — needs sign-off before implementation, same principles as before (one command per concept, variants become arguments, coven identity preserved, old names kept as hidden aliases for one release).

Housekeeping due this phase

• Remove the Phase 2 hidden aliases whose one-release grace period ends with the next release: /color, /vim, /voice, /statusline, /terminal-setup, /cost, /context, /undo, /revert.

Trivial duplicates (−3)

• /upgrade → alias of /update (today they're two visible commands with identical descriptions)
• /stats → /usage stats (keeps the TUI stats dialog reachable)
• /agents + /agent → single /agent (list/inspect/browse become arguments)

Sessions cluster (−5)

• /fork → /session fork
• /branch → /session branch
• /tag → /session tag
• /copy → /export copy [n] (re-opens the fix(tui): consolidate slash command surface #68 "keep" decision — /copy is a variant of exporting, not its own concept)
• /share → /export share

Auth cluster (−2)

• /switch → /login switch
• /refresh → /login refresh (or /providers refresh)

Modes cluster (−2)

• /think-back → /thinking back (with play as a sub-argument, preserving the Phase 1 /think-back play fold)
• /fast → /effort fast (debatable: it's a frequent mid-session toggle; decide)

Config cluster (−4)

• /keybindings → /config keybindings
• /theme → /config theme (theme picker overlay stays reachable)
• /output-style → /config output-style (already a /config set key; the standalone command is redundant)
• /import-config → /config import

Plugins / Coven cluster (−2)

• /reload-plugins → /plugin reload
• /managed-agents → /agent managed (or /coven agents)

Workflow (−1)

• /pr-comments → /review comments

Evaluate (pick ~4 to reach 40)

• /doctor → /status doctor?
• /add-dir → /session add-dir?
• /advisor → /config advisor? (re-opens the fix(tui): consolidate slash command surface #68 "keep" decision)
• /goal → /coven goal?

64 − 19 firm − ~4 evaluated ≈ 41 visible commands.

Named CLI commands (coven-code <name>) keep working regardless of slash folds — only the slash surface changes. As with Phase 2, keep deletions in focused commits to ease upstream Claurst merges (accepted divergence per COVEN.md).

Refs #59, docs/AUDIT-2026-06.md §4.

[BunsDev]

Sign-off (maintainer-approved 2026-06-11):

• Firm list: approved as written, including removal of the 9 expired Phase 2 hidden aliases (/color, /vim, /voice, /statusline, /terminal-setup, /cost, /context, /undo, /revert). Keep impls that serve as delegation targets of /config, /usage, /rewind — only the registry entries go.
• /fast: KEEP standalone. It's a high-frequency mid-session toggle; the fold isn't worth the friction. (Counts +1 against the target — acceptable.)
• Evaluate bucket: fold all four — /doctor → /status doctor, /add-dir → /session add-dir, /advisor → /config advisor, /goal → /coven goal.
• /refresh → /providers refresh (not /login refresh): it clears provider caches, so it's semantically a providers operation.
• /managed-agents placement as /agent managed (already in flight on the branch) is confirmed.

All folds keep old names as hidden one-release compatibility aliases, per the established pattern.

Net: 64 − 19 firm − 4 evaluated + 1 (/fast kept) ≈ 41–42 visible, within target tolerance.

[BunsDev]

Implemented in #78 — visible surface lands at 41 commands (64 → 41).

Decisions on the open items:

• Evaluate picks: /doctor → /status doctor, /add-dir → /session add-dir, /advisor → /config advisor, and /goal → /coven goal (the Coven surface owns durable autonomous work).
• Debatable folds confirmed: /fast → /effort fast (in the TUI it keeps the exact toggle behavior bare /fast had), /copy → /export copy.
• Phase 2 housekeeping: went ahead after all — v0.0.25 shipped the Phase 2 aliases, so their one-release grace period is served; feat(commands): Phase 3 consolidation — 64 → 41 visible slash commands (#73) #78 unregisters them.
• Bonus fix: the TUI intercept layer swallowed all argument forms (/rewind list, /session rename, /review security never reached the command layer); feat(commands): Phase 3 consolidation — 64 → 41 visible slash commands (#73) #78 makes it args-aware, which the folds required anyway.