Completes the issue-0089 backtick raw-identifier / `#import c` exemption
across all remaining identifier positions and closes three boundary gaps
the F0.6 review found.
1. Exhaustive raw-binding coverage. The `is_raw` bit now threads through
`ast.Identifier` and EVERY binding/capture form — `IfExpr`/`WhileExpr`
optional bindings, `ForExpr` capture + index, `MatchArm` capture,
`CatchExpr`/`OnFailStmt` tag bindings, `DestructureDecl` per-name, and
the protocol-default-body / foreign-class method param lists — not just
`var_decl`/`param`. `UnknownTypeChecker` skips the reserved-name check at
each arm when raw, so a backtick works in every identifier position while
a bare reserved spelling still errors (issue 0076 preserved).
2. Raw identifier is never a type. `parseTypeExpr`'s atom rejects a raw
identifier in type position (`x : `s2 = 1`, `List(`s2)`) with an accurate
diagnostic instead of silently type-classifying it.
3. Reserved-name function bare-callable. A bare `s2(4)` parses its callee as
a `.type_expr` (reserved spelling); `lowerCall` now rewrites a type_expr
callee to an identifier when a function of that name is in scope, so a
backtick-declared sx fn and a `#import c` foreign fn whose C name collides
with a reserved type spelling both resolve by their bare name.
(`TypeName(val)` is not a cast, so there is no ambiguity.)
Tests: examples/0152 (every control-flow/capture form + bare ref/call/member
access), examples/1054 (catch/onfail tag bindings), examples/1139 (raw in
type position rejected), examples/1220 extended (foreign reserved-name
function bare-call). 0076 negatives 1119/1121/1122/1123/1124/1125 stay green.
Gate: zig build + zig build test + 422 examples pass. specs.md + readme.md
updated; issues/0089 RESOLVED banner refreshed.
Reserved type-name spellings (s1, s2, u8, …) can now be used as value
identifiers two ways, resolving issue 0089:
1. Backtick raw identifier: a leading backtick (`s2) lexes to an
.identifier token carrying a new Token.is_raw flag, with the backtick
excluded from the text. A raw identifier is never type-classified — the
parser skips Type.fromName for it — so it is always a value identifier.
The flag threads to VarDecl.is_raw / Param.is_raw at binding sites, and
the reserved-type-name check (UnknownTypeChecker) skips raw bindings.
Because the token tag stays .identifier, the escape works in every
position (local, global, param, field, fn name, struct member, later
reference) with no per-site parser change.
2. #import c exemption: c_import.zig synthesizes foreign decls with
Param.is_raw = true, so generated C param names that collide with
reserved type names (s1, s2) import unedited.
A bare reserved-name binding in sx still errors (issue 0076 preserved):
the is_raw-gated skip only fires for backtick / foreign names, and a raw
binding's address-of / autoref lowering stays correct because every
occurrence is an .identifier, never a .type_expr.
Tests: examples/0151 (backtick, every position),
examples/1220 (foreign exemption, compiled+run), lexer unit tests.
1119 (bare-binding rejection) stays green. specs.md + readme.md updated.
