Lexer/parser: Pine line-wrapping rule + dangling Dedents between call arguments

[FellowTraveler]

Summary

This is the lexer/parser slice of #49, split out (as offered there) so each piece can be reviewed on its own. The code is unchanged from #49 — the commits are cherry-picked as-is. The three split PRs are independent: each compiles and passes the full workspace suite standalone (cargo test, just fmt-check, just clippy all clean on this branch), and any merge order is conflict-free.

Both fixes were found while running real published Pine strategies through pinecone bar-by-bar.

1. fix(parser): consume dangling Dedents between call arguments

A named argument whose value wraps onto an indented continuation line (the common table.cell(..., bgcolor = cond ? a :\n<indent>b, ...) idiom) leaves a closing Dedent in the token stream after the comma. arguments() only skipped Newline+Indent there, so the next argument failed to parse. The fix consumes such Dedents after a comma, guarded so the argument list's own closing Dedent (immediately followed by RParen) is preserved.

Test: multiline-ternary named argument followed by another argument — fails to parse before the fix.

2. feat(lexer): Pine's line-wrapping rule

Per the Pine Script reference (Line wrapping), a statement may wrap onto following lines as long as the continuation's indentation is not a multiple of 4 spaces — multiples of 4 are reserved for delimiting local blocks. The lexer treated every deeper line start as Indent, so this canonical published-script style failed with Unexpected token: And:

can_trade = trades_this_day < 2
         and under_profit_cap
         and above_loss_limit

The fix: at line start, when the indentation is not a multiple of 4, join the line to the previous logical line (drop the Newline that ended it; leave the indent stack untouched). The existing testdata corpus contains no non-multiple-of-4 indentation, so its behavior is unchanged — verified by the full suite.

Tests: lexer token-stream tests (a wrapped continuation emits no Indent/Dedent and no Newline before the continuation's operator; a 4-space block still emits Indent/Dedent), plus parser tests for a wrapped and-chain and a wrapped ternary inside an if block.

Note: the two commits are ordered — the lexer commit's parser tests build on the Dedent fix — so they travel together in this PR.

Validation

Beyond the tests in this PR, the combined change set (this PR plus its two siblings from #49) was validated externally: we run full Pine strategies through pinecone one bar at a time and diff the emitted entries/exits against TradingView's own strategy-tester CSV export for the same symbol/timeframe. With all of them in place, two real strategies match TV 100% — 56/56 signals on a 4H strategy and 21/21 on a daily strategy, including exit-reason order comments — over their full comparison windows.

[ferranbt]

LGTM! Only one comment.

[ferranbt]

Could you move these two tests to the testdata folder?