agent: read TOML literal-quoted Kimi model keys - #446

Thanks! The picker now lists [models.'kimi k2.5'] — confirmed the test fails before and passes after. Two things: (1) [models.'a'.'b'] now yields a bogus option a'.'b (main skipped it) — please reject the stripped name if it still contains '; (2) ownModel in kimi.go looks the key up as models."<key>", so after switching to a magpie model and back to default, a literal-keyed (or bare-keyed) model isn't restored and default_model ends up empty. Could you match tables by their decoded key in both places (one small helper), with a test that sets a magpie model and resets back to a '…'-keyed default?

Thanks, both fixed in 4e4d38c.

1. [models.'a'.'b'] is rejected now: a stripped name that still contains ' is not offered as an option.
2. The picker, restore and default check now share one helper that matches tables by their decoded key, so a '…'-keyed or bare-keyed default is restored after switching to a magpie model and back. Added a test that sets a magpie model and resets to a literal-keyed default, plus a nested-header case and a bare-key case.

internal/agent and internal/edit tests pass.

Thanks for the quick follow-up — re-reviewed at 4e4d38c and this looks good to merge.

• [models.'a'.'b'] is no longer offered (TestKimiNestedLiteralKeyIsNotAModel fails on dee2356, passes now).
• Restore goes through kimiModelTableForKey, so after magpie kimi magpie/<p>/<m> and magpie kimi default, a 'kimi k2.5'-keyed default comes back. In a sandbox HOME main drops default_model entirely; this branch restores "kimi k2.5". TestKimiRestoresDecodedModelKey (literal and bare) and TestKimiLiteralQuotedModelKey fail without the kimi.go change.
• Other header forms still behave: basic-quoted with escapes, bare, "dotted.name", 'lit.dot' and [ models . 'spaced key' ] are listed and resolve to their own tables; 'a'.b, "a".'b', kimi.sub and 'a'.'b'.'c' are skipped.

Merged onto current main cleanly; vet, the darwin/linux/windows builds and go test -tags nogui ./... all pass.