feat(piggy): piggy list/add/remove (v0.6.0)HEADv0.6.0master

New `piggy` group:
- `piggy list` lists piggy banks with saved/target amounts and linked
  accounts.
- `piggy add|remove <name|id> <amount> [--account NAME]` changes the
  saved amount on a linked account via PUT /piggy-banks/{id}.

Firefly syncs the whole account list on that PUT, so every linked account
is resent (others without current_amount, which keeps their value) or it
would be unlinked. Removing below zero is rejected before any write, and
the saved amount is read back so a refused add fails loudly instead of
returning 200 unchanged.

add/remove currently hit an upstream bug on Firefly III <= 6.7.9:
PiggyBankFactory::linkToAccountIds passes the pivot current_amount (an int
from the DB) to bcsub() uncast, so any PUT with "accounts" 500s
(firefly-iii/firefly-iii#13063). Documented in SKILL.md/README; the live
integration test skips on that error and runs once upstream is fixed.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/TODO.md b/TODO.md
index 3208c57..8c9a7de 100644
--- a/TODO.md
+++ b/TODO.md
@@ -8,7 +8,8 @@ bash completion).
 - [x] `budget` — list/create/delete/enable/disable, limit-list/limit-set, and
       `tx add --budget`. Shipped v0.4.0 (review follow-ups v0.4.1).
 - [ ] `bill` — list and inspect bills.
-- [ ] `piggy` — piggy banks.
+- [x] `piggy` — list/add/remove. Shipped v0.6.0. add/remove blocked upstream
+      by firefly-iii/firefly-iii#13063 (500 on PUT with accounts, <= 6.7.9).
 - [ ] `rule` — rules and rule groups.
 - [ ] `recurring` — recurring transactions.
 - [ ] `attachment` — list/download transaction attachments.