Capitalized keywords not recognized (case-sensitive keyword table)

• Type: bug (Track A — lexer)
• Status: DONE — 2026-06-23 (7d5b18d).
• Owner: — (Track A)
• Opened: 2026-06-23
• Closed: 2026-06-23
• Found by: Track A, following the capital-array keyword fix ([[project_synapse_recon_array_keyword]]) — the table was inconsistent.

Problem

Pascal keywords are case-insensitive in user code, but the lexer's Keyword() table matched most keywords by hard-coded lowercase characters (with ad-hoc Capital-first variants for only some). So capitalized / mixed-case reserved words fell through to identifiers and broke common mixed-case FPC/Delphi source:

Then Else Type Mod Case  ->  "Expected then/begin/), but got Then/Type/Mod/Case"
BEGIN END For To Do ...   ->  same class

Only array had been fixed individually before this.

Fix

Keyword() (lexer.inc) now lowercases the token once up front when not CaseSensitiveMode (user code), so every existing table entry matches any case. The compiler's own source is {$CASESENSITIVE ON}, so it keeps exact matching and self-host stays byte-identical.

One exception: forward is a DIRECTIVE, not a reserved word — FPC allows it as an ordinary identifier (procedure Forward(...), used in test/test_managed_var_param.pas). A non-exact-case match of forward reverts to an identifier, so forward (lowercase) is the directive while Forward/FORWARD stay identifiers.

Verification

test/test_keyword_case.pas (Type/For/To/Do/If/Then/Else/Mod/Case mixed-case), FPC objfpc oracle-matched (9 / 22). test/test_keyword_array_case.pas still green. make test + cross-bootstrap byte-identical; the Forward-as-identifier test (test_managed_var_param) passes.