The terminal's "What I can do" offers `u` and `p` only when there is a link to undo, and asks before it unlinks #7955

The terminal's "What I can do" screen now shows u (unlink the open-platform.sh login) only when there is a login to unlink, and p (unlink the parent forge) only when there is a parent link. Each key now asks before it unlinks, so an unlink that only the web page can undo is no longer one stray key press away.

• When a key is offered (src/tui/screens/can.ts): u appears in keys and is handled only when an edge token is active and linkedLogin finds a login. p appears only when parentIssuerOf is configured and linkedParent finds a link. With nothing to unlink, key returns false for both.
• The confirm: each key opens confirmScreen with yesNo: true. The question is "Unlink open-platform.sh login <login>?" or "Unlink the parent forge?", followed by "It is linked again from Settings on the web." y unlinks as before, with the same account.edge_unlinked / account.parent_unlinked bus events, and LAST_WAY_IN is still refused and shown. n or esc changes nothing.
• Tests (test/tui-can.test.ts): the two unlink tests now press y after the key. They also check the question's wording and that n (and esc for u) leave the link in place. A new test shows that with nothing linked, neither key is offered and pressing them opens nothing. Run against the old screen, 3 of the 4 tests fail.

bun test passes on test/tui-can.test.ts, test/tui-verify.test.ts, test/palette-roster.test.ts and test/tui-screens.test.ts. scripts/gate.ts, tsc --noEmit and design-lint are all clean. scripts/fast.ts named 211 files (about 17 minutes, over its 5-minute budget), so I ran the test files that open this screen instead and left the full run to the forge's check.

To try it: run ssh with the command in FORGE_APP_SSH, press ctrl-k and choose "What I can do". With nothing linked, there is no u or p in the key bar. With a link, pressing the key asks first.

🤖 Generated with Claude Code

Closes #7950

The terminal's "What I can do" screen now shows u (unlink the open-platform.sh login) only when there is a login to unlink, and p (unlink the parent forge) only when there is a parent link. Each key now asks before it unlinks, so an unlink that only the web page can undo is no longer one stray key press away.

• When a key is offered (src/tui/screens/can.ts): u appears in keys and is handled only when an edge token is active and linkedLogin finds a login. p appears only when parentIssuerOf is configured and linkedParent finds a link. With nothing to unlink, key returns false for both.
• The confirm: each key opens confirmScreen with yesNo: true. The question is "Unlink open-platform.sh login <login>?" or "Unlink the parent forge?", followed by "It is linked again from Settings on the web." y unlinks as before, with the same account.edge_unlinked / account.parent_unlinked bus events, and LAST_WAY_IN is still refused and shown. n or esc changes nothing.
• Tests (test/tui-can.test.ts): the two unlink tests now press y after the key. They also check the question's wording and that n (and esc for u) leave the link in place. A new test shows that with nothing linked, neither key is offered and pressing them opens nothing. Run against the old screen, 3 of the 4 tests fail.

bun test passes on test/tui-can.test.ts, test/tui-verify.test.ts, test/palette-roster.test.ts and test/tui-screens.test.ts. scripts/gate.ts, tsc --noEmit and design-lint are all clean. scripts/fast.ts named 211 files (about 17 minutes, over its 5-minute budget), so I ran the test files that open this screen instead and left the full run to the forge's check.

To try it: run ssh with the command in FORGE_APP_SSH, press ctrl-k and choose "What I can do". With nothing linked, there is no u or p in the key bar. With a link, pressing the key asks first.

🤖 Generated with Claude Code