feat(vba-extractor): detect statement-form calls after Then/Else in single-line If (closes #45)

[ardelperal]

Closes #45

Problem

\detectStatementCall\ and \detectQualifiedStatementCall\ (in \src/extraction/vba-extractor.ts) inspect only the FIRST identifier of the line. For \If x Then Foo arg\ the leading identifier is the keyword \If, which is in \CALL_KEYWORD_BLACKLIST, so the call AFTER \Then\ is silently dropped — even though the paren form \x.Method(...)\ on the same line is correctly captured by \CALL_RE. Same gap on the qualified path.

Result: the dominant VBA idiom for early-exit guards (\If Err.Number <> 0 Then GestionarError) contributed zero edges to the call graph, and the gap was inconsistent with the paren-form path.

Fix

Add \splitSingleLineIfClauses(line: string): string[]\ (Issue #45 helper):

• If the line matches ^If\s[\s\S]+?\bThen\b\s+\ (non-greedy condition, requires whitespace after \Then\ so block-form \If x Then\ is left for the existing per-line scan), the prefix is stripped and the body is split on \ Else \ (case-insensitive, statement-level only) and then on :\ (multi-statement). \GoTo\ / \Exit\ / \Resume\ clauses are filtered at the fragment level (defense in depth) before reaching the statement-call detectors.
• If the line does NOT match the single-line \If … Then\ shape, the splitter returns []\ so callers can use it unconditionally. Block-form \If\ keeps working through the existing per-line call-site scan that picks up the body on a subsequent line.

The two call-detection calls in \sweepCallsAndSql\ now iterate over the returned fragments instead of receiving the raw line. \CALL_RE\ (paren-form) is unchanged — it still scans the entire masked line as before, so \If x Then M(a) Else N(b)\ continues to emit both \M(a)\ and \N(b)\ edges via that path.

Tests

_tests_/extraction-vba.test.ts\ gains a new \describe('VbaExtractor — single-line \If … Then\ statement-form calls (Issue #45)', ...)\ block with 8 atoms that previously failed (red) and now pass (green):

1. \If Err.Number <> 0 Then GestionarError\ → emits \GestionarError\ (the canonical real-world case).
2. \If x Then Foo Else Bar\ → emits BOTH \Foo\ and \Bar\ calls edges.
3. \GoTo fin\ clause → silent (no edge to \GoTo*).
4. \Exit Sub\ clause → silent (no edge to \Exit).
5. Multi-statement \If x Then DoA: DoB\ (colon-separated) → emits both.
6. Block-form \If x Then\ with body on next line → unchanged (regression guard).
7. \Call\ keyword with statement-form arguments after \If … Then\ → still emits.
8. Qualified statement-call \m_Srv.Registrar 1\ after \If … Then\ → emits heuristic \Srv.Registrar\ stub (Fix 2 / #12a receiver-resolution path preserved).

Verification

• \pnpm test\ → 2065 passed, 41 skipped (skipped set is the pre-existing Windows + Node 25 environment skips listed in \AGENTS.md; nothing new skipped).
• \pnpm exec tsc --noEmit\ → clean.
• 324 lines changed across the two files; no other code touched.