feat(format): implement PL/pgSQL body formatting

* add formatBody and formatBodyInner functions for DECLARE section
* update needSpace to handle LBracket correctly
* enhance semanticallyEqual to compare dollar-quoted bodies
* add test data for broken layout scenarios

todo.md

@@ -38,22 +38,61 @@ Legend: ✅ done · 🚧 in progress · ⬜ not started
 - **Status:** all tests pass.
 - _Still TODO (later): DML/other-DDL structuring (currently Raw) for full formatting._
 
-### ⬜ PL/pgSQL body parser  ← NEXT (the remaining V1 piece)
-- Parse `$$ ... $$` bodies: DECLARE/BEGIN/END, IF/ELSIF/ELSE/END IF, LOOP/FOR/WHILE,
-  CASE, assignments (`:=` / `=`), RAISE, nested SQL statements, EXCEPTION blocks.
-- The crux for stored-procedure formatting (primary use case). Currently the body is
-  emitted verbatim; this milestone formats inside it. Reuse `inline`/spacing/casing from
-  `pkg/format` and keep verbatim fallback for unparsable constructs.
+### 🚧 PL/pgSQL body parser  ← NEXT (the remaining V1 piece)
+
+#### ✅ DECLARE section — `pkg/format/body.go`
+- `formatBody` splits the dollar-quote tag, calls `formatBodyInner`.
+- `formatBodyInner` locates `DECLARE` and `BEGIN` at depth 0, formats the declare block,
+  then emits `BEGIN` onwards verbatim.
+- `formatDeclareVars`: each variable declaration collapsed to one line
+  (`  name type [= expr];`), `--Block--` comment markers preserved on their own lines,
+  mid-declaration block comments trigger verbatim fallback.
+- `needSpace` fixed for `LBracket` — no space before `[` after ident/closing bracket
+  (fixes `citext[]`, array subscripts).
+- `semanticallyEqual` in tests updated to recurse into dollar-quoted body tokens so
+  whitespace normalization inside the body does not falsely fail the semantic check.
+- Added `testdata/corpus/test_a_broken.pgsql` — a CRLF corpus file with intentionally
+  broken layout (split-line variables + split-line body statements) used as a formatting
+  target; `testdata/corpus/test_a.pgsql` is the golden output.
+- **Status:** all tests pass; DECLARE section formats correctly.
+
+#### ⬜ Body statement formatter — `pkg/format/body.go` (next step)
+Two-phase formatter for the `BEGIN … END` block:
+
+1. **Block-depth tracker** — recognise `BEGIN`/`END`, `IF`/`THEN`/`ELSIF`/`ELSE`/`END IF`,
+   `LOOP`/`END LOOP`, `FOR`/`END LOOP`, `CASE`/`END CASE`, `EXCEPTION`/`WHEN` to maintain
+   current indent depth (`depth × 2` spaces).
+
+2. **Split-line join** — within each statement (tokens up to `;` at depth 0), a physical
+   line whose first non-whitespace token is at column 0 is a broken continuation; join it to
+   the preceding line with a single space. Exceptions: SQL clause keywords (`FROM`, `WHERE`,
+   `INTO`, `HAVING`, `GROUP`, `ORDER`, `RETURNING`) stay on their own line.
+
+3. **Base-indent normalisation** — after joining, each logical line is re-emitted at
+   `depth × 2` spaces, stripping its original leading whitespace and replacing it with the
+   computed indent. Internal relative indentation of multi-line expressions is preserved.
+
+4. **Blank-line preservation** — blank lines between statements in the original are kept
+   (they carry author intent about logical grouping).
+
+5. **Verbatim fallback** — any construct the formatter cannot classify cleanly passes
+   through verbatim, upholding invariant #4.
+
+Acceptance: `pgtidy fmt testdata/corpus/test_a_broken.pgsql` produces output matching
+`testdata/corpus/test_a.pgsql` (new golden-file test).
 
 ### ✅ Printer + style config — `pkg/format`, `pkg/config`
 - `pkg/config`: `Style` struct + `Default()` = house style (UPPERCASE keywords, lowercase
   types, 2-space indent, leading commas, spacing rules).
 - `pkg/format`: formats CREATE FUNCTION/PROCEDURE **headers** to house style (params
-  one-per-line leading-comma, option clauses each on own line, AS/`$$` own lines); body and
-  `Raw` statements emitted verbatim. Spacing engine (`needSpace`, tight ops `:: : -> ->>`)
-  + casing (`keywords`/`typeNames` sets). Comment-safety: verbatim fallback if a header
-  carries comments it cannot relocate.
-- Tests: golden header, idempotence, corpus idempotence + **semantic equivalence**.
+  one-per-line leading-comma, option clauses each on own line, AS/`$$` own lines); DECLARE
+  section formatted (see body parser entry); `Raw` statements emitted verbatim.
+  Spacing engine (`needSpace`, tight ops `:: : -> ->>`, array `[]`) + casing
+  (`keywords`/`typeNames` sets). Comment-safety: verbatim fallback if a header carries
+  comments it cannot relocate.
+- `pkg/format/body.go`: DECLARE section formatter (see body parser entry).
+- Tests: golden header, idempotence, corpus idempotence + **semantic equivalence**
+  (updated to recurse into dollar-quoted body tokens).
 - _Note: not a full Wadler Doc-IR yet — fixed-layout printer. Doc-IR for width-based
   expression wrapping can come when DML structuring lands._