feat: tx list --flat, account create --if-not-exists, --since/--until doc (v0.3.6)v0.3.6

Three smaller ISSUES.md items, one PATCH (two optional flags + a doc fix; no
existing caller or JSON shape changes).

- tx list --flat: emit one top-level object per split (journal id repeated),
  dropping the transactions[] nesting so single-split journals script cleanly.
  JSON-only; --human already explodes splits into a table.
- account create --if-not-exists: resolve the name first; on a clash return the
  existing account with "existed": true (exit 0) instead of surfacing Firefly's
  422, so import scripts are idempotent. Detects via resolver, not by parsing
  the error string.
- SKILL.md documents that --since/--until filter on the transaction date (the
  value date); Firefly journals have a single date field, no separate book date
  (verified against firefly-iii TimeCollection setRange).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/completions/firefly.bash b/completions/firefly.bash
index 648fbe0..6901d14 100644
--- a/completions/firefly.bash
+++ b/completions/firefly.bash
@@ -38,12 +38,12 @@ _firefly() {
     case "$group $leaf" in
         "auth set")         leaf_opts="--token --url";;
         "account balance")  leaf_opts="--at";;
-        "account create")   leaf_opts="--currency --opening-balance --type";;
+        "account create")   leaf_opts="--currency --if-not-exists --opening-balance --type";;
         "account list")     leaf_opts="--type";;
         "tx add")           leaf_opts="--category --date --desc --dry-run --from --skip-dupes --tags --to --type";;
         "tx delete")        leaf_opts="--yes";;
         "tx edit")          leaf_opts="--amount --category --date --desc --from --tags --to --type";;
-        "tx list")          leaf_opts="--account --all --limit --since --until";;
+        "tx list")          leaf_opts="--account --all --flat --limit --since --until";;
     esac
 
     # Leaves per group.