lints: adopt the canonical lints block

[h4x0r]

lints: adopt the canonical lints block

jsonguard had no [lints] block at all - no unsafe_code key, no
unwrap_used/expect_used, no pedantic. It now carries the canonical recipe
(CLAUDE.core.md "Rust Lint Posture") with the panic-lint superset:

unsafe_code = "forbid" (the crate contains no unsafe)
correctness / suspicious = "deny"
unwrap_used / expect_used = "deny"
all + pedantic = "warn", with the canonical cast_* allows

Nothing in production code used unwrap or expect - every such site was in
a test module, which now carries the sanctioned
#![cfg_attr(test, allow(...))] (and the integration test its own
top-level allow).

What the new lints surfaced, all fixed at the source:

clippy::match_same_arms 2 arms merged (types.rs collapses three
=> true arms; text.rs folds the C0,
DEL/C1 and bidi escapes into one arm)
clippy::format_push_string 3 replaced by a write_unicode_escape
helper over fmt::Write, which is also
what let the three arms merge
clippy::unnested_or_patterns 1 fixed
plus 3 machine-applicable fixes from clippy --fix

One allow is added, with its reason recorded in the manifest:

needless_pass_by_value 6 sites. The public API is deliberately
pub fn f<I: GuardInput>(input: I) - generic-by-value is the seam that
lets a caller pass &str, &[u8] or String unchanged. Taking &I would
break every caller and defeat the trait, so this is a false positive
against the design, not a defect to fix.

Gate: cargo build --all-targets --all-features, cargo test --all-features
(171 tests) and --no-default-features, cargo clippy --workspace
--all-targets --all-features -- -D warnings, cargo fmt --check - all clean.

Co-Authored-By: Claude Opus 5 (1M context) noreply@anthropic.com

🤖 Generated with Claude Code